Spinal Cord Module, Professor Frederick R Carrick.
The compulsory reading requirements for Prof Carrick's lecture on the
Spinal Cord are taken from Joynt and Griggs text CLINICAL NEUROLOGY
published by Lippincott-Raven
1 Chapter 43, Anatomy and Clinical Neurology of the Spinal Cord
2 Chapter 47, Trauma of the Spine and Spinal Cord
3 Chapter 48, Myelitis and Myelopathy
The reference list for this module is extensive due to the importance of
this information to those physicians that utilize spinal manipulation in
the treatment of neurological conditions. Prof Carrick's lecture
references are listed in this bibliography.
Bibliography
1. Abbott, F. V.; Hong, Y.; Franklin, K. B. The effect of lesions of the
dorsolateral funiculus on formalin pain and morphine
analgesia: a dose-response analysis. Pain. 1996 Apr; 65(1): 17-
23; ISSN: 0304-3959.
NETHERLANDS. There has been conflicting evidence concerning
the role of descending bulbospinal influences on pain and
opioid analgesia in the formalin test. We examined the effect
of lesions of the dorsolateral funiculus (DLF) on dose-effect
relations for formalin and morphine in the formalin test.
Experiment 1 showed that DLF lesions reduced the effect of 5
mg/kg morphine on pain in the tail-flick test, and eliminated
morphine's effect on pain produced by 2.5% formalin. When
lower concentrations of formalin were used, DLF lesions
produced hyperalgesia, indicated by a left shift 1.7-fold) of
the formalin concentration-response curve. In experiment 2,
DLF lesions increased the pain produced by 1.25% formalin and
shifted the dose-response relation for the effect of morphine
on the second phase of the pain response produced by 1.25%
formalin to 2.5-fold higher doses. The data show that DLF
lesions increase sensitivity to the pain-inducing effect of
formalin, and this accounts for a substantial component of the
effect of DLF lesions on morphine analgesia.. 0; 50-00-0; 57-
27-2.
2. Abbott, F. V.; Hong, Y.; Franklin, K. B. The effect of lesions of the
dorsolateral funiculus on formalin pain and morphine
analgesia: a dose-response analysis. Pain. 1996 Apr; 65(1): 17-
23; ISSN: 0304-3959.
NETHERLANDS. There has been conflicting evidence concerning
the role of descending bulbospinal influences on pain and
opioid analgesia in the formalin test. We examined the effect
of lesions of the dorsolateral funiculus (DLF) on dose-effect
relations for formalin and morphine in the formalin test.
Experiment 1 showed that DLF lesions reduced the effect of 5
mg/kg morphine on pain in the tail-flick test, and eliminated
morphine's effect on pain produced by 2.5% formalin. When
lower concentrations of formalin were used, DLF lesions
produced hyperalgesia, indicated by a left shift 1.7-fold) of
the formalin concentration-response curve. In experiment 2,
DLF lesions increased the pain produced by 1.25% formalin and
shifted the dose-response relation for the effect of morphine
on the second phase of the pain response produced by 1.25%
formalin to 2.5-fold higher doses. The data show that DLF
lesions increase sensitivity to the pain-inducing effect of
formalin, and this accounts for a substantial component of the
effect of DLF lesions on morphine analgesia.. 0; 50-00-0; 57-
27-2.
3. Agius, E.; Sagot, Y.; Duprat, A. M.; Cochard, P. Antibodies directed
against the beta 1-integrin subunit and peptides containing the
IKVAV sequence of laminin perturb neurite outgrowth of
peripheral neurons on immature spinal cord substrata.
Neuroscience. 1996 Apr; 71(3): 773-86; ISSN: 0306-4522.
UNITED-STATES. Neuron-substratum interactions regulating
axon growth in the developing central nervous system of the
rat have been studied by means of an in vitro bioassay: the
tissue section culture. We have previously shown that purified
chicken sensory or sympathetic neurons grown on natural
substrata consisting of cryostat sections of neonatal rat
spinal cord elaborate numerous long neurites [Sagot et al.
(1991) Brain Res. 543, 25-35]. Perturbation experiments, in
which neuron-substratum interactions are modified by
antibodies and peptides, have allowed us to analyse some of
the molecular determinants which control neurite outgrowth
in this system. Antibodies directed against the beta 1-integrin
subunit, one of the neuronal receptors for extracellular matrix
molecules, reduced the percentage of growing neurons by about
30% and the length of neurites by about 50%. In contrast,
antibodies directed against laminin-1 or fibronectin, two
extracellular matrix proteins transiently expressed in various
areas of the developing central nervous system, were unable to
block neurite outgrowth. Paradoxically, a peptide containing
the IKVAV sequence, which mimics an active sequence of the
laminin alpha 1 chain responsible for neurite extension, also
blocked neurite outgrowth on neonatal spinal cord substrata.
These results indicate that integrin receptors containing the
beta 1 subunit may play a role in regulating axon growth in the
developing nervous system. Among the putative extracellular
matrix ligands for these receptors, laminin and fibronectin do
not appear as prominent candidates in the neonatal spinal cord.
However, our data also suggest that the developing central
nervous system may contain neurite outgrowth-promoting
proteins carrying the IKVAV sequence, different from laminin-
1.. 0.
4. Agius, E.; Sagot, Y.; Duprat, A. M.; Cochard, P. Antibodies directed
against the beta 1-integrin subunit and peptides containing the
IKVAV sequence of laminin perturb neurite outgrowth of
peripheral neurons on immature spinal cord substrata.
Neuroscience. 1996 Apr; 71(3): 773-86; ISSN: 0306-4522.
UNITED-STATES. Neuron-substratum interactions regulating
axon growth in the developing central nervous system of the
rat have been studied by means of an in vitro bioassay: the
tissue section culture. We have previously shown that purified
chicken sensory or sympathetic neurons grown on natural
substrata consisting of cryostat sections of neonatal rat
spinal cord elaborate numerous long neurites [Sagot et al.
(1991) Brain Res. 543, 25-35]. Perturbation experiments, in
which neuron-substratum interactions are modified by
antibodies and peptides, have allowed us to analyse some of
the molecular determinants which control neurite outgrowth
in this system. Antibodies directed against the beta 1-integrin
subunit, one of the neuronal receptors for extracellular matrix
molecules, reduced the percentage of growing neurons by about
30% and the length of neurites by about 50%. In contrast,
antibodies directed against laminin-1 or fibronectin, two
extracellular matrix proteins transiently expressed in various
areas of the developing central nervous system, were unable to
block neurite outgrowth. Paradoxically, a peptide containing
the IKVAV sequence, which mimics an active sequence of the
laminin alpha 1 chain responsible for neurite extension, also
blocked neurite outgrowth on neonatal spinal cord substrata.
These results indicate that integrin receptors containing the
beta 1 subunit may play a role in regulating axon growth in the
developing nervous system. Among the putative extracellular
matrix ligands for these receptors, laminin and fibronectin do
not appear as prominent candidates in the neonatal spinal cord.
However, our data also suggest that the developing central
nervous system may contain neurite outgrowth-promoting
proteins carrying the IKVAV sequence, different from laminin-
1.. 0.
5. Anderson, B.; Rutledge, V. Age and hemisphere effects on
dendritic structure. Brain. 1996 Dec; 119( Pt 6): 1983-90;
ISSN: 0006-8950.
ENGLAND. The dendritic structures of 187 small supragranular
pyramidal neurons of the posterior superior temporal gyrus
were studied with rapid Golgi impregnations in postmortem
samples from 10 men aged 21-71 years. The number of primary
basilar dendritic branches, the total number of basilar
dendritic endings, the total basilar dendritic length, the total
number of visible basilar dendritic spines and the cell soma
sizes were all positively inter-correlated and all features
were correlated to age (r = -0.77, -0.88, -0.82, -0.72, -0.86,
respectively; all P < 0.05). These neuronal measures all
correlated with brain weight (r = 0.79*, 0.65*, 0.51, 0.45,
0.55, respectively; *denotes P < 0.05). A first principle
component derived from the inter-correlations of the neuronal
features plus brain weight correlated almost perfectly with
age (r = -0.93). The neuronal features differed between the
right and left hemispheres (Wilks' Lambda = 0.91, P < 0.01).
Post hoc tests showed that the dendritic trees of the right
hemisphere were longer (P = 0.002), more branched (P = 0.008)
and possessed more dendritic spines (P = 0.0009; Sheffe's
tests). In conclusion, there are hemispheric differences in the
dendritic structure of the small pyramidal neurons of
presumptive human speech cortex and its right hemisphere
analogue. Generalized neuronal atrophy is highly correlated
with both brain weight and age, and is a candidate process to
explain the decline in cognition with age.
6. Anderson, B.; Rutledge, V. Age and hemisphere effects on
dendritic structure. Brain. 1996 Dec; 119( Pt 6): 1983-90;
ISSN: 0006-8950.
ENGLAND. The dendritic structures of 187 small supragranular
pyramidal neurons of the posterior superior temporal gyrus
were studied with rapid Golgi impregnations in postmortem
samples from 10 men aged 21-71 years. The number of primary
basilar dendritic branches, the total number of basilar
dendritic endings, the total basilar dendritic length, the total
number of visible basilar dendritic spines and the cell soma
sizes were all positively inter-correlated and all features
were correlated to age (r = -0.77, -0.88, -0.82, -0.72, -0.86,
respectively; all P < 0.05). These neuronal measures all
correlated with brain weight (r = 0.79*, 0.65*, 0.51, 0.45,
0.55, respectively; *denotes P < 0.05). A first principle
component derived from the inter-correlations of the neuronal
features plus brain weight correlated almost perfectly with
age (r = -0.93). The neuronal features differed between the
right and left hemispheres (Wilks' Lambda = 0.91, P < 0.01).
Post hoc tests showed that the dendritic trees of the right
hemisphere were longer (P = 0.002), more branched (P = 0.008)
and possessed more dendritic spines (P = 0.0009; Sheffe's
tests). In conclusion, there are hemispheric differences in the
dendritic structure of the small pyramidal neurons of
presumptive human speech cortex and its right hemisphere
analogue. Generalized neuronal atrophy is highly correlated
with both brain weight and age, and is a candidate process to
explain the decline in cognition with age.
7. Andrew, E. R.; Inglis, B. A.; Kempka, M.; Mareci, T.; Szczesniak, E.
Magnetic field gradient system for nuclear magnetic resonance
microimaging. MAGMA. 1996 Jun; 4(2): 85-91; ISSN: 0968-
5243.
UNITED-STATES. In this study we present an orthogonal
magnetic field gradient system for nuclear magnetic
resonance (NMR) microimaging applications. The construction
details are given for a prototype assembly for proton
microscopy inside a 50-mm vertical bore magnet, which is
designed to fit into a commercial 300-MHz NMR probe. This
system has been used to acquire images of the human spinal
cord in vitro. Its performance has been evaluated and compared
to that predicted by computer simulation.
8. Andrew, E. R.; Inglis, B. A.; Kempka, M.; Mareci, T.; Szczesniak, E.
Magnetic field gradient system for nuclear magnetic resonance
microimaging. MAGMA. 1996 Jun; 4(2): 85-91; ISSN: 0968-
5243.
UNITED-STATES. In this study we present an orthogonal
magnetic field gradient system for nuclear magnetic
resonance (NMR) microimaging applications. The construction
details are given for a prototype assembly for proton
microscopy inside a 50-mm vertical bore magnet, which is
designed to fit into a commercial 300-MHz NMR probe. This
system has been used to acquire images of the human spinal
cord in vitro. Its performance has been evaluated and compared
to that predicted by computer simulation.
9. Araki, I.; De Groat, W. C. Unitary excitatory synaptic currents in
preganglionic neurons mediated by two distinct groups of
interneurons in neonatal rat sacral parasympathetic nucleus.
J-Neurophysiol. 1996 Jul; 76(1): 215-26; ISSN: 0022-3077.
UNITED-STATES. 1. Excitatory postsynaptic currents (EPSCs)
in parasympathetic preganglionic neurons (PGNs) were
examined by the use of the whole cell patch-clamp recording
technique in slice preparations of the neonatal rat lumbosacral
spinal cord. Synaptic responses were evoked in PGNs by
extracellular stimulation of a neighboring interneuron. 2.
Stimulation of interneurons medial to the sacral
parasympathetic nucleus (SPN) elicited EPSCs or inhibitory
postsynaptic currents in 58 and 11%, respectively, of PGNs.
Stimulation of interneurons dorsal to the SPN evoked EPSCs in
70% of PGNs. 3. EPSCs occurred at short latency (2.1 ms) and
were usually elicited in an all-or-none manner, indicating that
they were monosynaptic and mediated by a single interneuron
(i.e., unitary). 4. EPSCs were mediated by both non-N-methyl-
D-aspartate (non-NMDA) and NMDA receptors. 5. Unitary
excitatory postsynaptic potentials evoked by single stimuli
did not induce action potentials in PGNs, but repetitive
stimulation (> 20 Hz) of the single interneurons could evoke
firing of PGNs. 2-Amino-5-phosphonovalerate, an NMDA
receptor antagonist, reduced the synaptic depolarization
induced in PGNs by high-frequency interneuronal impulses. 6.
EPSCs mediated by dorsal interneurons were smaller in
amplitude (36.3 +/- 15.7 pA, mean +/- SD) than EPSCs
mediated by medial interneurons (88.4 +/- 45.7 pA). 7. Paired-
pulse facilitation of EPSCs was observed in PGNs (147.2 +/-
26.2%). The degree of facilitation was higher in dorsal (174.6
+/- 10.3%) than in medial interneuronal pathways (120.9 +/-
3.6%). Within each of interneuronal pathways the degree of
facilitation was independent of the magnitude of the unitary
EPSC. 8. The results show that PGNs receive monosynaptic
glutamatergic excitatory inputs from two distinct populations
of interneurons in the dorsal and medial regions of the SPN.
These two populations of interneurons are likely to have
different functions in the regulation of the preganglionic
outflow to the pelvic organs.. 0.
10. Araki, I.; De Groat, W. C. Unitary excitatory synaptic currents in
preganglionic neurons mediated by two distinct groups of
interneurons in neonatal rat sacral parasympathetic nucleus.
J-Neurophysiol. 1996 Jul; 76(1): 215-26; ISSN: 0022-3077.
UNITED-STATES. 1. Excitatory postsynaptic currents (EPSCs)
in parasympathetic preganglionic neurons (PGNs) were
examined by the use of the whole cell patch-clamp recording
technique in slice preparations of the neonatal rat lumbosacral
spinal cord. Synaptic responses were evoked in PGNs by
extracellular stimulation of a neighboring interneuron. 2.
Stimulation of interneurons medial to the sacral
parasympathetic nucleus (SPN) elicited EPSCs or inhibitory
postsynaptic currents in 58 and 11%, respectively, of PGNs.
Stimulation of interneurons dorsal to the SPN evoked EPSCs in
70% of PGNs. 3. EPSCs occurred at short latency (2.1 ms) and
were usually elicited in an all-or-none manner, indicating that
they were monosynaptic and mediated by a single interneuron
(i.e., unitary). 4. EPSCs were mediated by both non-N-methyl-
D-aspartate (non-NMDA) and NMDA receptors. 5. Unitary
excitatory postsynaptic potentials evoked by single stimuli
did not induce action potentials in PGNs, but repetitive
stimulation (> 20 Hz) of the single interneurons could evoke
firing of PGNs. 2-Amino-5-phosphonovalerate, an NMDA
receptor antagonist, reduced the synaptic depolarization
induced in PGNs by high-frequency interneuronal impulses. 6.
EPSCs mediated by dorsal interneurons were smaller in
amplitude (36.3 +/- 15.7 pA, mean +/- SD) than EPSCs
mediated by medial interneurons (88.4 +/- 45.7 pA). 7. Paired-
pulse facilitation of EPSCs was observed in PGNs (147.2 +/-
26.2%). The degree of facilitation was higher in dorsal (174.6
+/- 10.3%) than in medial interneuronal pathways (120.9 +/-
3.6%). Within each of interneuronal pathways the degree of
facilitation was independent of the magnitude of the unitary
EPSC. 8. The results show that PGNs receive monosynaptic
glutamatergic excitatory inputs from two distinct populations
of interneurons in the dorsal and medial regions of the SPN.
These two populations of interneurons are likely to have
different functions in the regulation of the preganglionic
outflow to the pelvic organs.. 0.
11. Aribal, M. E.; Gurcan, F.; Aslan, B. Chiari III malformation: MRI.
Neuroradiology. 1996 May; 38 Suppl 1: S184-6; ISSN: 0028-
3940.
GERMANY.
12. Aribal, M. E.; Gurcan, F.; Aslan, B. Chiari III malformation: MRI.
Neuroradiology. 1996 May; 38 Suppl 1: S184-6; ISSN: 0028-
3940.
GERMANY.
13. Armand, J.; Olivier, E.; Edgley, S. A.; Lemon, R. N. Postnatal
development of corticospinal projections from motor cortex to
the cervical enlargement in the macaque monkey. J-Neurosci.
1997 Jan 1; 17(1): 251-66; ISSN: 0270-6474.
UNITED-STATES. The postnatal development of corticospinal
projections was investigated in 11 macaques by means of the
anterograde transport of wheat germ agglutin-horseradish
peroxidase injected into the primary motor cortex hand area.
Although the fibers of the corticospinal tract reached all
levels of the spinal cord white matter at birth, their
penetration into the gray matter was far from complete. At
birth, as in the adult, corticospinal projections were
distributed to the same regions of the intermediate zone,
although they showed marked increases in density during the
first 5 months. The unique feature of the primate corticospinal
tract, namely direct cortico-motoneuronal projections to the
spinal motor nuclei innervating hand muscles, was not present
to a significant extent at birth. The density of these cortico-
motoneuronal projections increased rapidly during the first 5
months, followed by a protracted period extending into the
second year of life. The densest corticospinal terminations
occupied only 40% of the hand motor nuclei in the first
thoracic segment at 1 month, 73% at 5 months, and 75.5% at 3
years. A caudo-rostral gradient of termination density within
the hand motor nuclei was present throughout development and
persisted into the adult. As a consequence, the more caudal the
segment within the cervical enlargement, the earlier the adult
pattern of projection density was reached. No transitory
corticospinal projections were found. The continuous postnatal
expansion of cortico-motoneuronal projections to hand motor
nuclei in primates is in marked contrast to the retraction of
exuberant projections that characterizes the development of
other sensory and motor pathways in subprimates.. 0.
14. Armand, J.; Olivier, E.; Edgley, S. A.; Lemon, R. N. Postnatal
development of corticospinal projections from motor cortex to
the cervical enlargement in the macaque monkey. J-Neurosci.
1997 Jan 1; 17(1): 251-66; ISSN: 0270-6474.
UNITED-STATES. The postnatal development of corticospinal
projections was investigated in 11 macaques by means of the
anterograde transport of wheat germ agglutin-horseradish
peroxidase injected into the primary motor cortex hand area.
Although the fibers of the corticospinal tract reached all
levels of the spinal cord white matter at birth, their
penetration into the gray matter was far from complete. At
birth, as in the adult, corticospinal projections were
distributed to the same regions of the intermediate zone,
although they showed marked increases in density during the
first 5 months. The unique feature of the primate corticospinal
tract, namely direct cortico-motoneuronal projections to the
spinal motor nuclei innervating hand muscles, was not present
to a significant extent at birth. The density of these cortico-
motoneuronal projections increased rapidly during the first 5
months, followed by a protracted period extending into the
second year of life. The densest corticospinal terminations
occupied only 40% of the hand motor nuclei in the first
thoracic segment at 1 month, 73% at 5 months, and 75.5% at 3
years. A caudo-rostral gradient of termination density within
the hand motor nuclei was present throughout development and
persisted into the adult. As a consequence, the more caudal the
segment within the cervical enlargement, the earlier the adult
pattern of projection density was reached. No transitory
corticospinal projections were found. The continuous postnatal
expansion of cortico-motoneuronal projections to hand motor
nuclei in primates is in marked contrast to the retraction of
exuberant projections that characterizes the development of
other sensory and motor pathways in subprimates.. 0.
15. Asada, H.; Yamaguchi, Y.; Tsunoda, S.; Fukuda, Y. The role of spinal
cord activation before neurectomy in the development of
autotomy. Pain. 1996 Jan; 64(1): 161-7; ISSN: 0304-3959.
NETHERLANDS. A model of deafferentation pain is provided by
sectioning the sciatic and saphenous nerves in the rat and
mouse. This procedure leads to self-mutilation of the
denervated hindpaw (autotomy). A noxious stimulus to the
denervated area before neurectomy is known to enhance the
autotomy. To understand the mechanism underlying this
enhancement by prior noxious stimuli, we examined the
effects of intrathecal (i.t.) injection of substance P (SP) and
somatostatin (SOM) on autotomy behavior. These peptides are
known to be released from primary afferent terminals in the
dorsal horn by noxious stimuli. A single i.t. injection of SP or
SOM just before neurectomy dramatically enhanced autotomy
behavior in mice. Autotomy was enhanced in a dose-dependent
manner with i.t. injection of SP (0.1-20 nmol) 5 min before
neurectomy or SOM (0.1-1.0 nmol) 20 min before neurectomy.
Autotomy significantly decreased by extending the interval
between i.t. injection of SP or SOM and neurectomy. Intact
mice injected with the same doses of SP or SOM showed dose-
dependent acute nociceptive responses directed to the
hindpaw. The severity of autotomy in neurectomized mice and
the duration of acute nociceptive responses induced by the
same doses of SP or SOM in intact mice were related. These
results suggest that neuropeptides applied to the spinal dorsal
horn just before deafferentation induce a state of central
neural activation with long-lasting effects on the function of
CNS cells. Augmentation of autotomy is a result of this
activation which is kept as a 'memory'.. 33507-63-0; 51110-
01-1.
16. Asada, H.; Yamaguchi, Y.; Tsunoda, S.; Fukuda, Y. The role of spinal
cord activation before neurectomy in the development of
autotomy. Pain. 1996 Jan; 64(1): 161-7; ISSN: 0304-3959.
NETHERLANDS. A model of deafferentation pain is provided by
sectioning the sciatic and saphenous nerves in the rat and
mouse. This procedure leads to self-mutilation of the
denervated hindpaw (autotomy). A noxious stimulus to the
denervated area before neurectomy is known to enhance the
autotomy. To understand the mechanism underlying this
enhancement by prior noxious stimuli, we examined the
effects of intrathecal (i.t.) injection of substance P (SP) and
somatostatin (SOM) on autotomy behavior. These peptides are
known to be released from primary afferent terminals in the
dorsal horn by noxious stimuli. A single i.t. injection of SP or
SOM just before neurectomy dramatically enhanced autotomy
behavior in mice. Autotomy was enhanced in a dose-dependent
manner with i.t. injection of SP (0.1-20 nmol) 5 min before
neurectomy or SOM (0.1-1.0 nmol) 20 min before neurectomy.
Autotomy significantly decreased by extending the interval
between i.t. injection of SP or SOM and neurectomy. Intact
mice injected with the same doses of SP or SOM showed dose-
dependent acute nociceptive responses directed to the
hindpaw. The severity of autotomy in neurectomized mice and
the duration of acute nociceptive responses induced by the
same doses of SP or SOM in intact mice were related. These
results suggest that neuropeptides applied to the spinal dorsal
horn just before deafferentation induce a state of central
neural activation with long-lasting effects on the function of
CNS cells. Augmentation of autotomy is a result of this
activation which is kept as a 'memory'.. 33507-63-0; 51110-
01-1.
17. Ataka, H.; Murakami, M.; Goto, S.; Moriya, H.; Hayashi, F.; Fukuda, Y.
Effects of hypoxia on the ventral root motor-evoked potential
in the in vitro spinal cord preparation. Spine. 1996 Sep 15;
21(18): 2095-100; ISSN: 0362-2436.
UNITED-STATES. STUDY DESIGN: This study investigated the
effects of hypoxia and glucose on motor functions of spinal
cord, monitoring ventral root motor-evoked potential in the in
vitro cervical cord preparations. OBJECTIVE: To study
ischemia-induced changes in ventral root motor-evoked
potential of spinal cord. SUMMARY OF BACKGROUND DATA:
Previous studies demonstrated ischemic changes caused by
local circulatory impairment might be a major
pathophysiologic basis of neuron damage in cord compression.
METHODS: Ventral root motor-evoked potential elicited by
stimulation of ventrolateral funiculus was recorded from the
ventral root in the isolated spinal cord preparations obtained
from a newborn rat. The preparations were exposed to
artificial cerebrospinal fluid equilibrated with severe or mild
hypoxia for 90 minutes. Inhibitory and excitatory
neurotransmitter antagonists were added to artificial
cerebrospinal fluid to investigate synaptic transmission. The
artificial cerebrospinal fluids containing various
concentrations of glucose were used to study the glucose's
effects. RESULTS: Ventral root motor-evoked potential
consisted of the early and late components, which were
excitatory transsynaptic potentials. The amplitudes were
increased in the early phase of severe hypoxia and declined in
the prolonged exposure. In mild hypoxia, there was a sustained
increase of the amplitudes. The application of inhibitory
neurotransmitter antagonists abolished the augmentation of
the amplitudes in the early phase of severe hypoxia. Hypoxia
without glucose accelerated hypoxic change. CONCLUSION:
Inhibitory synaptic transmission was depressed preferentially
in the early phase of severe hypoxia or in mild hypoxia.
Excitatory and inhibitory transmissions were suppressed in
prolonged severe hypoxia. Glucose deficiency aggravated
hypoxic inhibition of synaptic transmissions.. 124-87-8; 50-
99-7; 57-24-9.
18. Ataka, H.; Murakami, M.; Goto, S.; Moriya, H.; Hayashi, F.; Fukuda, Y.
Effects of hypoxia on the ventral root motor-evoked potential
in the in vitro spinal cord preparation. Spine. 1996 Sep 15;
21(18): 2095-100; ISSN: 0362-2436.
UNITED-STATES. STUDY DESIGN: This study investigated the
effects of hypoxia and glucose on motor functions of spinal
cord, monitoring ventral root motor-evoked potential in the in
vitro cervical cord preparations. OBJECTIVE: To study
ischemia-induced changes in ventral root motor-evoked
potential of spinal cord. SUMMARY OF BACKGROUND DATA:
Previous studies demonstrated ischemic changes caused by
local circulatory impairment might be a major
pathophysiologic basis of neuron damage in cord compression.
METHODS: Ventral root motor-evoked potential elicited by
stimulation of ventrolateral funiculus was recorded from the
ventral root in the isolated spinal cord preparations obtained
from a newborn rat. The preparations were exposed to
artificial cerebrospinal fluid equilibrated with severe or mild
hypoxia for 90 minutes. Inhibitory and excitatory
neurotransmitter antagonists were added to artificial
cerebrospinal fluid to investigate synaptic transmission. The
artificial cerebrospinal fluids containing various
concentrations of glucose were used to study the glucose's
effects. RESULTS: Ventral root motor-evoked potential
consisted of the early and late components, which were
excitatory transsynaptic potentials. The amplitudes were
increased in the early phase of severe hypoxia and declined in
the prolonged exposure. In mild hypoxia, there was a sustained
increase of the amplitudes. The application of inhibitory
neurotransmitter antagonists abolished the augmentation of
the amplitudes in the early phase of severe hypoxia. Hypoxia
without glucose accelerated hypoxic change. CONCLUSION:
Inhibitory synaptic transmission was depressed preferentially
in the early phase of severe hypoxia or in mild hypoxia.
Excitatory and inhibitory transmissions were suppressed in
prolonged severe hypoxia. Glucose deficiency aggravated
hypoxic inhibition of synaptic transmissions.. 124-87-8; 50-
99-7; 57-24-9.
19. Barnes, P. D. Atypical idiopathic scoliosis in childhood. Semin-
Pediatr-Neurol. 1996 Sep; 3(3): 207-11; ISSN: 1071-9091.
UNITED-STATES. Scoliosis, common in preadolescent females
is a finding which warrants investigation in any other age
group or if the clinical or neuroimaging features are atypical
even in the preadolescent female. The cause of scoliosis are
numerous but include several important conditions some of
which are treatable and some of which are genetic. A rational
approach to sequencing the neuroimaging studies to be used is
based on what the clinical suspicions are and the results of
the initial studies.
20. Barnes, P. D. Atypical idiopathic scoliosis in childhood. Semin-
Pediatr-Neurol. 1996 Sep; 3(3): 207-11; ISSN: 1071-9091.
UNITED-STATES. Scoliosis, common in preadolescent females
is a finding which warrants investigation in any other age
group or if the clinical or neuroimaging features are atypical
even in the preadolescent female. The cause of scoliosis are
numerous but include several important conditions some of
which are treatable and some of which are genetic. A rational
approach to sequencing the neuroimaging studies to be used is
based on what the clinical suspicions are and the results of
the initial studies.
21. Beardsley, T. Steps to recovery. Researchers finding ways of
coaxing spinal nerves to grow [news]. Sci-Am. 1997 Jan;
276(1): 26, 28; ISSN: 0036-8733.
UNITED-STATES.
22. Beardsley, T. Steps to recovery. Researchers finding ways of
coaxing spinal nerves to grow [news]. Sci-Am. 1997 Jan;
276(1): 26, 28; ISSN: 0036-8733.
UNITED-STATES.
23. Bjartmar, C. Oligodendroglial sheath lengths in developing rat
ventral funiculus and corpus callosum. Neurosci-Lett. 1996
Sep 27; 216(2): 85-8; ISSN: 0304-3940.
IRELAND. The lengths of uncompacted and partly compacted
oligodendroglial sheaths in the developing rat spinal cord (SC)
ventral funiculus (ages F19 and F21) and corpus callosum (CC;
ages P12 and P17) were studied by serial section electron
microscopy. The average newly formed uncompacted sheath is
21 and 33 microns long in the SC (F19) and CC (P12),
respectively, many being less than 10 microns. In these early
series, approximately 2/3 of the analysed axon length is
unensheathed. The average partly compacted sheath is 102 and
69 microns long in the SC (F21) and CC (P17), respectively.
Here, about 1/3 of the examined axon length is unensheathed.
These results suggest that oligodendroglial sheaths initially
are very short, and that they elongate actively before and
during compaction. The limited unensheathed space along these
axons indicate that some early sheaths must be eliminated.
24. Bjartmar, C. Oligodendroglial sheath lengths in developing rat
ventral funiculus and corpus callosum. Neurosci-Lett. 1996
Sep 27; 216(2): 85-8; ISSN: 0304-3940.
IRELAND. The lengths of uncompacted and partly compacted
oligodendroglial sheaths in the developing rat spinal cord (SC)
ventral funiculus (ages F19 and F21) and corpus callosum (CC;
ages P12 and P17) were studied by serial section electron
microscopy. The average newly formed uncompacted sheath is
21 and 33 microns long in the SC (F19) and CC (P12),
respectively, many being less than 10 microns. In these early
series, approximately 2/3 of the analysed axon length is
unensheathed. The average partly compacted sheath is 102 and
69 microns long in the SC (F21) and CC (P17), respectively.
Here, about 1/3 of the examined axon length is unensheathed.
These results suggest that oligodendroglial sheaths initially
are very short, and that they elongate actively before and
during compaction. The limited unensheathed space along these
axons indicate that some early sheaths must be eliminated.
25. Blomqvist, A.; Ericson, A. C.; Craig, A. D.; Broman, J. Evidence for
glutamate as a neurotransmitter in spinothalamic tract
terminals in the posterior region of owl monkeys. Exp-Brain-
Res. 1996 Feb; 108(1): 33-44; ISSN: 0014-4819.
GERMANY. Previous studies have suggested that glutamate is a
neurotransmitter in ascending somatosensory pathways to the
thalamus. The present study examined with quantitative
immunohistochemical methods the presence of glutamate in
spinothalamic tract terminals of owl monkeys (Aotus
trivirgatus). Such terminals in the posterior region, in which a
nucleus was recently identified as a specific pain and
temperature relay in macaques and humans, were labeled by
anterograde transport of wheat germ agglutinin conjugated to
horseradish peroxidase, injected into the spinal dorsal horn.
Glutamate-like immunoreactivity was demonstrated with a
postembedding immunogold procedure using a well-
characterized glutamate antiserum. Quantitative analysis of
the immunogold labeling demonstrated that the spinothalamic
tract terminals contained more than twice the tissue average
of glutamate-like immunoreactivity. Enrichment of glutamate-
like immunoreactivity was also found in terminals of
presumed cortical origin. Presynaptic dendrites, cell bodies
and non-vesicle-containing dendrites displayed low levels of
glutamate-like immunoreactivity. A strong positive
correlation (r = 0.69; P < 0.0001) was found between the
density of synaptic vesicles and the density of gold particles
in spinothalamic tract terminals, in contrast to a weak
negative relationship (r = -0.28; P = 0.089) present in
GABAergic presynaptic dendrites. These data provide strong
evidence that the gold labeling in the spinothalamic tract
terminals represents transmitter labeling, implying that
glutamate is a neurotransmitter for ascending nociceptive and
thermoreceptive information in primates.. 0; 56-86-0.
26. Blomqvist, A.; Ericson, A. C.; Craig, A. D.; Broman, J. Evidence for
glutamate as a neurotransmitter in spinothalamic tract
terminals in the posterior region of owl monkeys. Exp-Brain-
Res. 1996 Feb; 108(1): 33-44; ISSN: 0014-4819.
GERMANY. Previous studies have suggested that glutamate is a
neurotransmitter in ascending somatosensory pathways to the
thalamus. The present study examined with quantitative
immunohistochemical methods the presence of glutamate in
spinothalamic tract terminals of owl monkeys (Aotus
trivirgatus). Such terminals in the posterior region, in which a
nucleus was recently identified as a specific pain and
temperature relay in macaques and humans, were labeled by
anterograde transport of wheat germ agglutinin conjugated to
horseradish peroxidase, injected into the spinal dorsal horn.
Glutamate-like immunoreactivity was demonstrated with a
postembedding immunogold procedure using a well-
characterized glutamate antiserum. Quantitative analysis of
the immunogold labeling demonstrated that the spinothalamic
tract terminals contained more than twice the tissue average
of glutamate-like immunoreactivity. Enrichment of glutamate-
like immunoreactivity was also found in terminals of
presumed cortical origin. Presynaptic dendrites, cell bodies
and non-vesicle-containing dendrites displayed low levels of
glutamate-like immunoreactivity. A strong positive
correlation (r = 0.69; P < 0.0001) was found between the
density of synaptic vesicles and the density of gold particles
in spinothalamic tract terminals, in contrast to a weak
negative relationship (r = -0.28; P = 0.089) present in
GABAergic presynaptic dendrites. These data provide strong
evidence that the gold labeling in the spinothalamic tract
terminals represents transmitter labeling, implying that
glutamate is a neurotransmitter for ascending nociceptive and
thermoreceptive information in primates.. 0; 56-86-0.
27. Blottner, D.; Wolf, N.; Lachmund, A.; Flanders, K. C.; Unsicker, K.
TGF-beta rescues target-deprived preganglionic sympathetic
neurons in the spinal cord. Eur-J-Neurosci. 1996 Jan; 8(1):
202-10; ISSN: 0953-816X.
ENGLAND. Transforming growth factors beta (TGF-beta), a
family of pleiotropic cytokines, are widely distributed in the
developing and adult nervous system. In order to further
determine the neural functions of TGF-beta, we have localized
the TGF-beta isoforms 1, 2 and 3 in the adult rat adrenal
medulla and studied the neuroprotective capacity of one
representative family member, TGF-beta 2, for those spinal
cord neurons which innervate adrenal chromaffin cells and
which die after destruction of the adrenal medulla. Unilateral
electrothermal destruction of the adrenal medulla led to the
disappearance of 25% of sympathetic preganglionic neurons,
which are located in the intermediolateral (IML) column of
thoracic spinal cord segments 7-10 and can be selectively
marked by NADPH-diaphorase. The neurons which disappeared
following adrenomedullectomy constitute the full set of
neurons that innervate the adrenal medulla. Implantation of
gelfoam soaked with 0.5 micrograms TGF-beta 2 into the
adrenal wound cavity rescued all spinal cord neurons in the IML
ipsilaterally to the lesioned side. Cytochrome c was not
effective. Injections of [125I]TGF-beta 2 into the adrenal
medulla did not result in retrograde transport and subsequent
labelling of spinal cord neurons, suggesting that TGF-beta may
exert its neuroprotective actions by indirect mechanisms.
TGF-beta applied to cultured adrenocortical cells did not
overtly increase the amount of mRNA for fibroblast growth
factor-2, an established trophic molecule for sympathetic
preganglionic spinal cord neurons. The mechanisms by which
TGF-beta exerts its neurotrophic effect are therefore unclear.
Even so, our data provide the first evidence that TGF-beta may
play an important role in vivo in the control of maintenance of
a population of spinal cord neurons.. EC 1.6.99.1; 0; 0; 0; 0;
9007-43-6.
28. Blottner, D.; Wolf, N.; Lachmund, A.; Flanders, K. C.; Unsicker, K.
TGF-beta rescues target-deprived preganglionic sympathetic
neurons in the spinal cord. Eur-J-Neurosci. 1996 Jan; 8(1):
202-10; ISSN: 0953-816X.
ENGLAND. Transforming growth factors beta (TGF-beta), a
family of pleiotropic cytokines, are widely distributed in the
developing and adult nervous system. In order to further
determine the neural functions of TGF-beta, we have localized
the TGF-beta isoforms 1, 2 and 3 in the adult rat adrenal
medulla and studied the neuroprotective capacity of one
representative family member, TGF-beta 2, for those spinal
cord neurons which innervate adrenal chromaffin cells and
which die after destruction of the adrenal medulla. Unilateral
electrothermal destruction of the adrenal medulla led to the
disappearance of 25% of sympathetic preganglionic neurons,
which are located in the intermediolateral (IML) column of
thoracic spinal cord segments 7-10 and can be selectively
marked by NADPH-diaphorase. The neurons which disappeared
following adrenomedullectomy constitute the full set of
neurons that innervate the adrenal medulla. Implantation of
gelfoam soaked with 0.5 micrograms TGF-beta 2 into the
adrenal wound cavity rescued all spinal cord neurons in the IML
ipsilaterally to the lesioned side. Cytochrome c was not
effective. Injections of [125I]TGF-beta 2 into the adrenal
medulla did not result in retrograde transport and subsequent
labelling of spinal cord neurons, suggesting that TGF-beta may
exert its neuroprotective actions by indirect mechanisms.
TGF-beta applied to cultured adrenocortical cells did not
overtly increase the amount of mRNA for fibroblast growth
factor-2, an established trophic molecule for sympathetic
preganglionic spinal cord neurons. The mechanisms by which
TGF-beta exerts its neurotrophic effect are therefore unclear.
Even so, our data provide the first evidence that TGF-beta may
play an important role in vivo in the control of maintenance of
a population of spinal cord neurons.. EC 1.6.99.1; 0; 0; 0; 0;
9007-43-6.
29. Bonfanti, L.; Merighi, A.; Theodosis, D. T. Dorsal rhizotomy induces
transient expression of the highly sialylated isoform of the
neural cell adhesion molecule in neurons and astrocytes of the
adult rat spinal cord. Neuroscience. 1996 Oct; 74(3): 619-23;
ISSN: 0306-4522.
UNITED-STATES. Expression of the weakly adhesive, highly
sialylated isoform of the neural cell adhesion molecule is a
feature common to cell capable of migration and conformation
changes. 11,18,19 Polysialylated neural cell adhesion molecule
also intervenes in axonal outgrowth and synaptogenesis during
development and after lesion. 11,13 High levels of
polysialylated neural cell adhesion molecule immunoreactivity
are normally visible in laminae I,II and X of the adult rat
spinal cord. 2,15 We how here that unilateral cervical dorsal
rhizotomy induced no detectable changes in immunoreactivity
in these areas. However, 24 h after lesion, polysialylated
neural cell adhesion molecule immunoreactivity appeared in
neurons scattered in laminae III-IX, ipsi-and contralateral to
lesion. This reaction increased particularly on the
contralateral side, became maximal at four days and
disappeared eight days later. At this time, there was
immunolabelling of astrocytes with an activated morphology.
The astrocytic labelling, predominant on the side ipsilateral to
the lesion, was strongest 12 days after rhizotomy, then
diminished progressively. Deafferentation thus causes a
transient expression of polysialylated neural cell adhesion
molecule within areas of the spinal cord distinct from those
which permanently express this adhesion molecule. Such
expression occurs both in neurons and glial cells, with a
temporal pattern specific to each type of cell.. 0; 0.
30. Bonfanti, L.; Merighi, A.; Theodosis, D. T. Dorsal rhizotomy induces
transient expression of the highly sialylated isoform of the
neural cell adhesion molecule in neurons and astrocytes of the
adult rat spinal cord. Neuroscience. 1996 Oct; 74(3): 619-23;
ISSN: 0306-4522.
UNITED-STATES. Expression of the weakly adhesive, highly
sialylated isoform of the neural cell adhesion molecule is a
feature common to cell capable of migration and conformation
changes. 11,18,19 Polysialylated neural cell adhesion molecule
also intervenes in axonal outgrowth and synaptogenesis during
development and after lesion. 11,13 High levels of
polysialylated neural cell adhesion molecule immunoreactivity
are normally visible in laminae I,II and X of the adult rat
spinal cord. 2,15 We how here that unilateral cervical dorsal
rhizotomy induced no detectable changes in immunoreactivity
in these areas. However, 24 h after lesion, polysialylated
neural cell adhesion molecule immunoreactivity appeared in
neurons scattered in laminae III-IX, ipsi-and contralateral to
lesion. This reaction increased particularly on the
contralateral side, became maximal at four days and
disappeared eight days later. At this time, there was
immunolabelling of astrocytes with an activated morphology.
The astrocytic labelling, predominant on the side ipsilateral to
the lesion, was strongest 12 days after rhizotomy, then
diminished progressively. Deafferentation thus causes a
transient expression of polysialylated neural cell adhesion
molecule within areas of the spinal cord distinct from those
which permanently express this adhesion molecule. Such
expression occurs both in neurons and glial cells, with a
temporal pattern specific to each type of cell.. 0; 0.
31. Borja, A. Z. M.; Murphy, C.; Zeller, R. AltFGF-2, a novel ER-
associated FGF-2 protein isoform: its embryonic distribution
and functional analysis during neural tube development. Dev-
Biol. 1996 Dec 15; 180(2): 680-92; ISSN: 0012-1606.
UNITED-STATES. A novel fibroblast growth factor-2 (FGF-2)
protein isoform, called altFGF-2, is expressed abundantly
during chicken embryogenesis. The amino-terminal domain of
the 21.5-kDa altFGF-2 protein diverges completely from the
other three FGF-2 proteins due to alternative splicing of their
first coding exons. Furthermore, the altFGF-2 protein, in
contrast to FGF-2 proteins, is targeted predominantly to the
endoplasmic reticulum. In chicken embryos, altFGF-2 and FGF-
2 proteins are differentially distributed in several
mesodermal structures including developing limbs and kidneys.
All four FGF-2 protein isoforms are also expressed in the
developing neural tube from early neural plate stages onward.
In contrast to FGF-2 proteins, the altFGF-2 isoform is
distributed in a dynamic, spatially restricted pattern in
notochord and ventral neural tube (floor plate and motor
neurons) during specification of neuronal populations. To study
the possible shared or differential signaling functions of
chicken altFGF-2 and FGF-2 gene products, they were
ectopically expressed in the dorsal neural tube aspect of
transgenic mouse embryos. Dorsal expression of altFGF-2, but
not FGF-2 gene products, induced alteration of neural tube
morphology in a significant fraction of mouse embryos (25%).
However, no alterations of dorsoventral (d/v) neural tube
polarity were detected, indicating that altFGF-2 and FGF-2
gene products either function as permissive cofactors or
regulate neural tube growth without affecting establishment
of its primary d/v polarity.. 0.
32. Borja, A. Z. M.; Murphy, C.; Zeller, R. AltFGF-2, a novel ER-
associated FGF-2 protein isoform: its embryonic distribution
and functional analysis during neural tube development. Dev-
Biol. 1996 Dec 15; 180(2): 680-92; ISSN: 0012-1606.
UNITED-STATES. A novel fibroblast growth factor-2 (FGF-2)
protein isoform, called altFGF-2, is expressed abundantly
during chicken embryogenesis. The amino-terminal domain of
the 21.5-kDa altFGF-2 protein diverges completely from the
other three FGF-2 proteins due to alternative splicing of their
first coding exons. Furthermore, the altFGF-2 protein, in
contrast to FGF-2 proteins, is targeted predominantly to the
endoplasmic reticulum. In chicken embryos, altFGF-2 and FGF-
2 proteins are differentially distributed in several
mesodermal structures including developing limbs and kidneys.
All four FGF-2 protein isoforms are also expressed in the
developing neural tube from early neural plate stages onward.
In contrast to FGF-2 proteins, the altFGF-2 isoform is
distributed in a dynamic, spatially restricted pattern in
notochord and ventral neural tube (floor plate and motor
neurons) during specification of neuronal populations. To study
the possible shared or differential signaling functions of
chicken altFGF-2 and FGF-2 gene products, they were
ectopically expressed in the dorsal neural tube aspect of
transgenic mouse embryos. Dorsal expression of altFGF-2, but
not FGF-2 gene products, induced alteration of neural tube
morphology in a significant fraction of mouse embryos (25%).
However, no alterations of dorsoventral (d/v) neural tube
polarity were detected, indicating that altFGF-2 and FGF-2
gene products either function as permissive cofactors or
regulate neural tube growth without affecting establishment
of its primary d/v polarity.. 0.
33. Bosio, A.; Binczek, E.; Stoffel, W. Functional breakdown of the
lipid bilayer of the myelin membrane in central and peripheral
nervous system by disrupted galactocerebroside synthesis.
Proc-Natl-Acad-Sci-U-S-A. 1996 Nov 12; 93(23): 13280-5;
ISSN: 0027-8424.
UNITED-STATES. The lipid bilayer of the myelin membrane of
the central nervous system (CNS) and the peripheral nervous
system (PNS) contains the oligodendrocyte- and Schwann cell-
specific glycosphingolipids galactocerebrosides (GalC) and
GalC-derived sulfatides (sGalC). We have generated a UDP-
galactose ceramide galactosyltransferase (CGT) null mutant
mouse (cgt-/-) with CNS and PNS myelin completely depleted
of GalC and derived sGalC. Oligodendrocytes and Schwann cells
are unable to restore the structure and function of these
galactosphingolipids to maintain the insulator function of the
membrane bilayer. The velocity of nerve conduction of
homozygous cgt-/- mice is reduced to that of unmyelinated
axons. This indicates a severely altered ion permeability of
the lipid bilayer. GalC and sGalC are essential for the
unperturbed lipid bilayer of the myelin membrane of CNS and
PNS. The severe dysmyelinosis leads to death of the cgt-/-
mouse at the end of the myelination period.. EC 2.4.1.-; EC
2.4.1.62; 0; 0; 0.
34. Bosio, A.; Binczek, E.; Stoffel, W. Functional breakdown of the
lipid bilayer of the myelin membrane in central and peripheral
nervous system by disrupted galactocerebroside synthesis.
Proc-Natl-Acad-Sci-U-S-A. 1996 Nov 12; 93(23): 13280-5;
ISSN: 0027-8424.
UNITED-STATES. The lipid bilayer of the myelin membrane of
the central nervous system (CNS) and the peripheral nervous
system (PNS) contains the oligodendrocyte- and Schwann cell-
specific glycosphingolipids galactocerebrosides (GalC) and
GalC-derived sulfatides (sGalC). We have generated a UDP-
galactose ceramide galactosyltransferase (CGT) null mutant
mouse (cgt-/-) with CNS and PNS myelin completely depleted
of GalC and derived sGalC. Oligodendrocytes and Schwann cells
are unable to restore the structure and function of these
galactosphingolipids to maintain the insulator function of the
membrane bilayer. The velocity of nerve conduction of
homozygous cgt-/- mice is reduced to that of unmyelinated
axons. This indicates a severely altered ion permeability of
the lipid bilayer. GalC and sGalC are essential for the
unperturbed lipid bilayer of the myelin membrane of CNS and
PNS. The severe dysmyelinosis leads to death of the cgt-/-
mouse at the end of the myelination period.. EC 2.4.1.-; EC
2.4.1.62; 0; 0; 0.
35. Bowen, B. C.; DePrima, S.; Pattany, P. M.; Marcillo, A.; Madsen, P.;
Quencer, R. M. MR angiography of normal intradural vessels of
the thoracolumbar spine. AJNR-Am-J-Neuroradiol. 1996 Mar;
17(3): 483-94; ISSN: 0195-6108.
UNITED-STATES. PURPOSE: To identify and describe the normal
intradural vessels detected on MR angiograms of the
thoracolumbar spine. METHODS: Six adult subjects who had
clinical evidence of myelopathy, yet normal findings at spinal
digital subtraction angiography (DSA), were also studied
without and with contrast-enhanced MR imaging and three-
dimensional time-of-flight, single-slab MR angiography.
Sagittal and coronal subvolume (targeted) maximum intensity
projection images were compared with arterial and venous
phase DSA images. Angiographic images were then compared
with postmortem, formalin-fixed cord specimens. RESULTS:
Recognizable intradural vessels were detected only on
contrast-enhanced MR angiograms. These vessels corresponded
to the posterior and/or anterior median (midline) veins and the
great medullary veins. The median veins had variable but mild
tortuosity. The medullary veins, which extended from the
median veins and coronal venous plexus on the cord surface to
the epidural venous plexus, were relatively straight and
usually located at T-12 or L-1. The anterior spinal artery
could partially contribute to the anterior midline vascular
signal. CONCLUSION: The intradural vessels identified on
contrast-enhanced MR angiograms are primarily veins, and
these are usually the largest vessels on or near the cord
surface. The limited number and minimal tortuosity of these
veins may serve as a baseline for the examination of patients
with clinically suspected arteriovenous malformation or
fistula.
36. Bowen, B. C.; DePrima, S.; Pattany, P. M.; Marcillo, A.; Madsen, P.;
Quencer, R. M. MR angiography of normal intradural vessels of
the thoracolumbar spine. AJNR-Am-J-Neuroradiol. 1996 Mar;
17(3): 483-94; ISSN: 0195-6108.
UNITED-STATES. PURPOSE: To identify and describe the normal
intradural vessels detected on MR angiograms of the
thoracolumbar spine. METHODS: Six adult subjects who had
clinical evidence of myelopathy, yet normal findings at spinal
digital subtraction angiography (DSA), were also studied
without and with contrast-enhanced MR imaging and three-
dimensional time-of-flight, single-slab MR angiography.
Sagittal and coronal subvolume (targeted) maximum intensity
projection images were compared with arterial and venous
phase DSA images. Angiographic images were then compared
with postmortem, formalin-fixed cord specimens. RESULTS:
Recognizable intradural vessels were detected only on
contrast-enhanced MR angiograms. These vessels corresponded
to the posterior and/or anterior median (midline) veins and the
great medullary veins. The median veins had variable but mild
tortuosity. The medullary veins, which extended from the
median veins and coronal venous plexus on the cord surface to
the epidural venous plexus, were relatively straight and
usually located at T-12 or L-1. The anterior spinal artery
could partially contribute to the anterior midline vascular
signal. CONCLUSION: The intradural vessels identified on
contrast-enhanced MR angiograms are primarily veins, and
these are usually the largest vessels on or near the cord
surface. The limited number and minimal tortuosity of these
veins may serve as a baseline for the examination of patients
with clinically suspected arteriovenous malformation or
fistula.
37. Boxall, S. J.; Thompson, S. W.; Dray, A.; Dickenson, A. H.; Urban, L.
Metabotropic glutamate receptor activation contributes to
nociceptive reflex activity in the rat spinal cord in vitro.
Neuroscience. 1996 Sep; 74(1): 13-20; ISSN: 0306-4522.
UNITED-STATES. The contribution of metabotropic glutamate
receptor activation to the spinal segmental reflex response
evoked at high-intensity electrical stimulation suggesting a
role in nociception, has been examined in an in vitro
preparation of neonatal rat spinal cord. Segmental reflex
responses were recorded as a ventral root depolarization
evoked following drug perfusion to the spinal cord or by
electrical activation of high-threshold nociceptive afferent
fibres. Superfusion of the selective metabotropic glutamate
receptor agonist, (1S, 3R)-1-aminocyclopentane-1,3-
dicarboxylic acid [(1S,3R)-ACPD], to the spinal cord produced a
dose-dependent, reversible ventral root depolarization (EC50 =
58 +/- 7 microM; n = 4), which was antagonized by the
selective metabotropic glutamate receptor antagonist, (+)-
alpha-methyl-4-carboxyphenylglycine (MCPG; IC50 = 243 +/-
61 microM; n = 4). MCPG, over the same concentration range
(10 microM-5.0 mM) did not affect N-methyl-D-aspartate-
induced ventral root depolarizations. In contrast, the specific
N-methyl-D-aspartate receptor antagonist D(-)-2-amino-5-
phosphonopentanoic acid (D-AP5) reduced N-methyl-D-
aspartate-evoked ventral root depolarization but did not
affect the depolarization evoked by (1S,3R)-ACPD, thus
indicating the specificity of the antagonists for these
aggregate responses. MCPG significantly reduced the prolonged
phase of the single shock C-fibre-evoked ventral root
depolarization (IC50 = 2.9 +/- 0.2 mM; n = 3-5). Low frequency
high intensity stimulation of the dorsal root evoked a wind-up
response, the amplitude of which was attenuated by both D-
AP5 and MCPG in a dose-dependent manner. The ventral root
depolarization evoked by capsaicin application (1.0 microM, 30
s) was blocked by both MCPG (IC50 = 809 +/- 35 microM; n = 4)
and D-AP5 (IC50 = 143 +/- 43 microM; n = 4). These data
suggest that both D-AP5 and MCPG reduced C-fibre-induced
ventral root responses. In addition to N-methyl-D-aspartate
receptor, metabotropic glutamate receptor activation appears
to be involved in the generation of the segmental spinal reflex
evoked by high-intensity stimulation in the neonatal rat spinal
cord in vitro.. 0; 6384-92-5; 77521-29-0.
38. Boxall, S. J.; Thompson, S. W.; Dray, A.; Dickenson, A. H.; Urban, L.
Metabotropic glutamate receptor activation contributes to
nociceptive reflex activity in the rat spinal cord in vitro.
Neuroscience. 1996 Sep; 74(1): 13-20; ISSN: 0306-4522.
UNITED-STATES. The contribution of metabotropic glutamate
receptor activation to the spinal segmental reflex response
evoked at high-intensity electrical stimulation suggesting a
role in nociception, has been examined in an in vitro
preparation of neonatal rat spinal cord. Segmental reflex
responses were recorded as a ventral root depolarization
evoked following drug perfusion to the spinal cord or by
electrical activation of high-threshold nociceptive afferent
fibres. Superfusion of the selective metabotropic glutamate
receptor agonist, (1S, 3R)-1-aminocyclopentane-1,3-
dicarboxylic acid [(1S,3R)-ACPD], to the spinal cord produced a
dose-dependent, reversible ventral root depolarization (EC50 =
58 +/- 7 microM; n = 4), which was antagonized by the
selective metabotropic glutamate receptor antagonist, (+)-
alpha-methyl-4-carboxyphenylglycine (MCPG; IC50 = 243 +/-
61 microM; n = 4). MCPG, over the same concentration range
(10 microM-5.0 mM) did not affect N-methyl-D-aspartate-
induced ventral root depolarizations. In contrast, the specific
N-methyl-D-aspartate receptor antagonist D(-)-2-amino-5-
phosphonopentanoic acid (D-AP5) reduced N-methyl-D-
aspartate-evoked ventral root depolarization but did not
affect the depolarization evoked by (1S,3R)-ACPD, thus
indicating the specificity of the antagonists for these
aggregate responses. MCPG significantly reduced the prolonged
phase of the single shock C-fibre-evoked ventral root
depolarization (IC50 = 2.9 +/- 0.2 mM; n = 3-5). Low frequency
high intensity stimulation of the dorsal root evoked a wind-up
response, the amplitude of which was attenuated by both D-
AP5 and MCPG in a dose-dependent manner. The ventral root
depolarization evoked by capsaicin application (1.0 microM, 30
s) was blocked by both MCPG (IC50 = 809 +/- 35 microM; n = 4)
and D-AP5 (IC50 = 143 +/- 43 microM; n = 4). These data
suggest that both D-AP5 and MCPG reduced C-fibre-induced
ventral root responses. In addition to N-methyl-D-aspartate
receptor, metabotropic glutamate receptor activation appears
to be involved in the generation of the segmental spinal reflex
evoked by high-intensity stimulation in the neonatal rat spinal
cord in vitro.. 0; 6384-92-5; 77521-29-0.
39. Brackett, N. L.; Padron, O. F.; Lynne, C. M. Semen quality of spinal
cord injured men is better when obtained by vibratory
stimulation versus electroejaculation. J-Urol. 1997 Jan;
157(1): 151-7; ISSN: 0022-5347.
UNITED-STATES. PURPOSE: Most spinal cord injured men
require assisted ejaculation procedures to obtain semen, and
the majority can achieve this result by vibratory stimulation
or electroejaculation. We determined if semen obtained by
vibratory stimulation differed in quality from that obtained by
electroejaculation. MATERIALS AND METHODS: Between
subjects and within subjects designs were used. Of 77 spinal
cord injured men 23 underwent vibratory stimulation only, 44
electroejaculation only and 10 both procedures. Antegrade,
retrograde and total ejaculates were analyzed in each subject
for total sperm count, percent motile sperm and percent sperm
with rapid linear motion. RESULTS: With vibratory stimulation
compared to electroejaculation the percent motile sperm and
percent sperm with rapid linear motion were significantly
greater, whereas total sperm count was similar, in the
antegrade specimens and total ejaculates. This finding was
true for different groups of subjects as well as within a group
of the same subjects. CONCLUSIONS: Semen obtained by
vibratory stimulation is of better quality than that obtained by
electroejaculation. In medical practices that include assisted
ejaculation of spinal cord injured men, we recommend
obtaining a specimen by vibratory stimulation. If that method
fails electroejaculation should be performed.
40. Brackett, N. L.; Padron, O. F.; Lynne, C. M. Semen quality of spinal
cord injured men is better when obtained by vibratory
stimulation versus electroejaculation. J-Urol. 1997 Jan;
157(1): 151-7; ISSN: 0022-5347.
UNITED-STATES. PURPOSE: Most spinal cord injured men
require assisted ejaculation procedures to obtain semen, and
the majority can achieve this result by vibratory stimulation
or electroejaculation. We determined if semen obtained by
vibratory stimulation differed in quality from that obtained by
electroejaculation. MATERIALS AND METHODS: Between
subjects and within subjects designs were used. Of 77 spinal
cord injured men 23 underwent vibratory stimulation only, 44
electroejaculation only and 10 both procedures. Antegrade,
retrograde and total ejaculates were analyzed in each subject
for total sperm count, percent motile sperm and percent sperm
with rapid linear motion. RESULTS: With vibratory stimulation
compared to electroejaculation the percent motile sperm and
percent sperm with rapid linear motion were significantly
greater, whereas total sperm count was similar, in the
antegrade specimens and total ejaculates. This finding was
true for different groups of subjects as well as within a group
of the same subjects. CONCLUSIONS: Semen obtained by
vibratory stimulation is of better quality than that obtained by
electroejaculation. In medical practices that include assisted
ejaculation of spinal cord injured men, we recommend
obtaining a specimen by vibratory stimulation. If that method
fails electroejaculation should be performed.
41. Brennan, T. J.; Olson, E. N.; Klein, W. H.; Winslow, J. W. Extensive
motor neuron survival in the absence of secondary skeletal
muscle fiber formation. J-Neurosci-Res. 1996 Jul 1; 45(1): 57-
68; ISSN: 0360-4012.
UNITED-STATES. Mice with a null mutation in the myogenic
basic helixloop-helix regulatory gene myogenin have severe
developmental muscle defects resulting in loss of secondary
muscle fibers and perinatal death. In this study, we used the
myogenin mutant mouse as a model to study the effects of the
loss of secondary muscle fibers and the contribution of
primary muscle fibers on the survival of motor neurons during
programmed cell death. We demonstrate that in the absence of
secondary skeletal muscle fibers there is complete survival of
facial motor nucleus motor neurons and approximately 60%
survival of spinal lumbar motor neurons in the myogenin
mutant mouse. The surviving spinal motor neurons maintain
axonal projections into the hindlimb and display aspects of
synaptic contact into the remaining rudimentary fibers. These
findings suggest that primary muscle fibers, representing
approximately 10% of normal muscle mass, contribute
significantly to the control of motor neuron cell survival in
mammals.. 0.
42. Brennan, T. J.; Olson, E. N.; Klein, W. H.; Winslow, J. W. Extensive
motor neuron survival in the absence of secondary skeletal
muscle fiber formation. J-Neurosci-Res. 1996 Jul 1; 45(1): 57-
68; ISSN: 0360-4012.
UNITED-STATES. Mice with a null mutation in the myogenic
basic helixloop-helix regulatory gene myogenin have severe
developmental muscle defects resulting in loss of secondary
muscle fibers and perinatal death. In this study, we used the
myogenin mutant mouse as a model to study the effects of the
loss of secondary muscle fibers and the contribution of
primary muscle fibers on the survival of motor neurons during
programmed cell death. We demonstrate that in the absence of
secondary skeletal muscle fibers there is complete survival of
facial motor nucleus motor neurons and approximately 60%
survival of spinal lumbar motor neurons in the myogenin
mutant mouse. The surviving spinal motor neurons maintain
axonal projections into the hindlimb and display aspects of
synaptic contact into the remaining rudimentary fibers. These
findings suggest that primary muscle fibers, representing
approximately 10% of normal muscle mass, contribute
significantly to the control of motor neuron cell survival in
mammals.. 0.
43. Britton, N. F.; Chaplain, M. A.; Skevington, S. M. The role of N-
methyl-D-aspartate (NMDA) receptors in wind-up: a
mathematical model. IMA-J-Math-Appl-Med-Biol. 1996 Sep;
13(3): 193-205; ISSN: 0265-0746.
ENGLAND. We present a mathematical model for the
phenomenon of wind-up (Mendell, 1966, Exper. Neur. 16,316-
22) which occurs in many neurons. We concentrate on its
occurrence in the substantia gelatinosa of the dorsal horns of
the spinal cord, where it is connected with certain
pathological and nonpathological pain states. The model is a
development of the model by Britton & Skevington (1989, J.
Theor. Biol. 137, 91-105) for Melzack & Wall's gate control
theory of pain (1965, Science, New York, 150, 971-9; 1982,
The Challenge of Pain, Penguin: Harmondsworth), modified to
take account of more recent information. Its variables are the
electric potentials of various cells in the midbrain and the
spinal cord. Britton & Skevington's original model simulated
many of the phenomena observed in acute pain in humans, but
not the wind-up mechanism. This is not surprising, since this
model did not include the N-methyl-D-aspartate (NMDA)
receptors that are now recognized as being crucial to the
phenomenon. Here we rectify this omission, and obtain good
agreement between the model and experimental data on wind-
up. The positive feedback that NMDA receptors exhibit is
shown to be the essential feature in producing wind-up. As an
independent test of the model we simulate a completely
different experimental set-up, and obtain good qualitative
agreement with data there. Finally, we present a prediction of
the model that has yet to be tested experimentally.. 0.
44. Britton, N. F.; Chaplain, M. A.; Skevington, S. M. The role of N-
methyl-D-aspartate (NMDA) receptors in wind-up: a
mathematical model. IMA-J-Math-Appl-Med-Biol. 1996 Sep;
13(3): 193-205; ISSN: 0265-0746.
ENGLAND. We present a mathematical model for the
phenomenon of wind-up (Mendell, 1966, Exper. Neur. 16,316-
22) which occurs in many neurons. We concentrate on its
occurrence in the substantia gelatinosa of the dorsal horns of
the spinal cord, where it is connected with certain
pathological and nonpathological pain states. The model is a
development of the model by Britton & Skevington (1989, J.
Theor. Biol. 137, 91-105) for Melzack & Wall's gate control
theory of pain (1965, Science, New York, 150, 971-9; 1982,
The Challenge of Pain, Penguin: Harmondsworth), modified to
take account of more recent information. Its variables are the
electric potentials of various cells in the midbrain and the
spinal cord. Britton & Skevington's original model simulated
many of the phenomena observed in acute pain in humans, but
not the wind-up mechanism. This is not surprising, since this
model did not include the N-methyl-D-aspartate (NMDA)
receptors that are now recognized as being crucial to the
phenomenon. Here we rectify this omission, and obtain good
agreement between the model and experimental data on wind-
up. The positive feedback that NMDA receptors exhibit is
shown to be the essential feature in producing wind-up. As an
independent test of the model we simulate a completely
different experimental set-up, and obtain good qualitative
agreement with data there. Finally, we present a prediction of
the model that has yet to be tested experimentally.. 0.
45. Budai, D.; Larson, A. A. Role of substance P in the modulation of C-
fiber-evoked responses of spinal dorsal horn neurons. Brain-
Res. 1996 Feb 26; 710(1-2): 197-203; ISSN: 0006-8993.
NETHERLANDS. Substance P (SP) as well as excitatory amino
acids (EAAs) appear to be released in response to stimulation
of primary afferent C-fibers. Activity at N-methyl-D-
aspartate (NMDA) receptors is essential for wind-up (the
progressive potentiation of C-fiber-evoked responses of single
neurons in response to an electrical stimulation), however, the
role of SP in wind-up is unclear. To address this, the effects
of iontophoretically applied CP-99,994 (a NK-1 receptor
antagonist), SP and SP(1-7) (an N-terminal breakdown product
of SP), were compared on responses of spinal dorsal horn wide
dynamic range (WDR) neurons of the rat. Post-stimulus time
histograms (PSTH) were summed over 12 responses to low
frequency (0.5 Hz) electrical stimulation of the cutaneous
receptive field. Changes in responses of dorsal horn neurons
were evaluated by monitoring C-fiber input, wind-up, and the
total number of spikes evoked by C-fiber activity in response
to the 12 stimuli. The NK-1 receptor antagonist CP-99,994
significantly inhibited the total number of C-spikes and
caused a significant reduction in wind-up without changing the
C-fiber input, indicating the involvement of NK-1 receptors in
wind-up. Application of SP led to an overall increase in the
total number of C-fiber evoked responses of dorsal horn
neurons and C-fiber input, however, wind-up, as defined, was
significantly decreased following SP. In contrast, substance
P(1-7) evoked a long-lasting increase in the total number of
C-fiber-related spikes which was initially sustained by a
transient increase in the input followed by a longer lasting
increase in wind-up, an effect opposite that of CP-99,994. As
NMDA activity has been previously shown to be inhibited and
then potentiated by SP N-terminal activity over a similar time
interval, the present data are consistent with the mediation of
wind-up by NMDA and its modulation by SP N-terminal activity.
Release of SP in response to noxious stimulation may,
therefore, increase primary afferent C-fiber activity (input)
whereas an accumulation of SP N-terminal metabolites
appears to potentiate wind-up, perhaps via positive
modulation of EAA activity.. 0; 0; 0; 136982-36-0; 33507-63-
0; 72226-88-1.
46. Budai, D.; Larson, A. A. Role of substance P in the modulation of C-
fiber-evoked responses of spinal dorsal horn neurons. Brain-
Res. 1996 Feb 26; 710(1-2): 197-203; ISSN: 0006-8993.
NETHERLANDS. Substance P (SP) as well as excitatory amino
acids (EAAs) appear to be released in response to stimulation
of primary afferent C-fibers. Activity at N-methyl-D-
aspartate (NMDA) receptors is essential for wind-up (the
progressive potentiation of C-fiber-evoked responses of single
neurons in response to an electrical stimulation), however, the
role of SP in wind-up is unclear. To address this, the effects
of iontophoretically applied CP-99,994 (a NK-1 receptor
antagonist), SP and SP(1-7) (an N-terminal breakdown product
of SP), were compared on responses of spinal dorsal horn wide
dynamic range (WDR) neurons of the rat. Post-stimulus time
histograms (PSTH) were summed over 12 responses to low
frequency (0.5 Hz) electrical stimulation of the cutaneous
receptive field. Changes in responses of dorsal horn neurons
were evaluated by monitoring C-fiber input, wind-up, and the
total number of spikes evoked by C-fiber activity in response
to the 12 stimuli. The NK-1 receptor antagonist CP-99,994
significantly inhibited the total number of C-spikes and
caused a significant reduction in wind-up without changing the
C-fiber input, indicating the involvement of NK-1 receptors in
wind-up. Application of SP led to an overall increase in the
total number of C-fiber evoked responses of dorsal horn
neurons and C-fiber input, however, wind-up, as defined, was
significantly decreased following SP. In contrast, substance
P(1-7) evoked a long-lasting increase in the total number of
C-fiber-related spikes which was initially sustained by a
transient increase in the input followed by a longer lasting
increase in wind-up, an effect opposite that of CP-99,994. As
NMDA activity has been previously shown to be inhibited and
then potentiated by SP N-terminal activity over a similar time
interval, the present data are consistent with the mediation of
wind-up by NMDA and its modulation by SP N-terminal activity.
Release of SP in response to noxious stimulation may,
therefore, increase primary afferent C-fiber activity (input)
whereas an accumulation of SP N-terminal metabolites
appears to potentiate wind-up, perhaps via positive
modulation of EAA activity.. 0; 0; 0; 136982-36-0; 33507-63-
0; 72226-88-1.
47. Burke, R. E.; Glenn, L. L. Horseradish peroxidase study of the
spatial and electrotonic distribution of group Ia synapses on
type-identified ankle extensor motoneurons in the cat. J-
Comp-Neurol. 1996 Aug 26; 372(3): 465-85; ISSN: 0021-9967.
UNITED-STATES. Eight functionally identified group Ia muscle
afferents from triceps surae or plantaris muscles were
labeled intraaxonally with horseradish peroxidase (HRP) in
seven adult cats. Subsequently, HRP was injected into two to
six homonymous or heteronymous alpha-motoneurons per
animal (total = 22), each identified by motor unit type and
located near the site of afferent injection. The complete
trajectories of labeled afferents were reconstructed, and
putative synaptic contacts on HRP-labeled motoneurons were
identified at high magnification. Dendritic paths from each
contact were also mapped and measured. A total of 24 contact
systems (the combination of a group Ia afferent and a
postsynaptic motoneuron) were reconstructed, of which 17
were homonymous, and seven were heteronymous. Overall,
homonymous contact systems had an average of 9.6 boutons,
whereas heteronymous contact systems had an average of 5.9
boutons. The average number of boutons found on type S
motoneurons in homonymous contact systems was smaller
(6.4, range 3-17) than in systems involving types FF or FR
motoneurons (FF: 10.4, range 4-18; FR: 11.3, range 4-32).
Neither of these differences were statistically significant. In
contrast to earlier reports, a majority (15/24) of contact
systems included more than one collateral from the same Ia
afferent. The complexity (number of branch points) in the
arborization pathway leading to each contact (overall mean 8.4
+/- 3.3) was virtually identical in all contact systems,
irrespective of the type of postsynaptic motoneuron. The
three-dimensional distribution of group Ia contacts was not
coextensive with the radially organized dendrites of
motoneurons: Dendrites oriented in the ventromedial to
dorsolateral axis had the fewest (8%) contacts, whereas
rostrocaudal dendrites had the most (63%) contacts.
Nevertheless, contacts were widely distributed on the
motoneuron surface, with few on and near the soma (< or = 200
microns radial distance from the soma) or on the most distal
parts of the tree (> or = 1,000 microns). The boutons in
individual contact systems also showed wide spatial and
estimated electrotonic distributions; only 3/24 systems had
all contact located within a restricted spatial/electrotonic
region. The relations between these anatomical results and
existing electrophysiological data on group Ia synaptic
potentials are discussed.. EC 1.11.1.-.
48. Burke, R. E.; Glenn, L. L. Horseradish peroxidase study of the
spatial and electrotonic distribution of group Ia synapses on
type-identified ankle extensor motoneurons in the cat. J-
Comp-Neurol. 1996 Aug 26; 372(3): 465-85; ISSN: 0021-9967.
UNITED-STATES. Eight functionally identified group Ia muscle
afferents from triceps surae or plantaris muscles were
labeled intraaxonally with horseradish peroxidase (HRP) in
seven adult cats. Subsequently, HRP was injected into two to
six homonymous or heteronymous alpha-motoneurons per
animal (total = 22), each identified by motor unit type and
located near the site of afferent injection. The complete
trajectories of labeled afferents were reconstructed, and
putative synaptic contacts on HRP-labeled motoneurons were
identified at high magnification. Dendritic paths from each
contact were also mapped and measured. A total of 24 contact
systems (the combination of a group Ia afferent and a
postsynaptic motoneuron) were reconstructed, of which 17
were homonymous, and seven were heteronymous. Overall,
homonymous contact systems had an average of 9.6 boutons,
whereas heteronymous contact systems had an average of 5.9
boutons. The average number of boutons found on type S
motoneurons in homonymous contact systems was smaller
(6.4, range 3-17) than in systems involving types FF or FR
motoneurons (FF: 10.4, range 4-18; FR: 11.3, range 4-32).
Neither of these differences were statistically significant. In
contrast to earlier reports, a majority (15/24) of contact
systems included more than one collateral from the same Ia
afferent. The complexity (number of branch points) in the
arborization pathway leading to each contact (overall mean 8.4
+/- 3.3) was virtually identical in all contact systems,
irrespective of the type of postsynaptic motoneuron. The
three-dimensional distribution of group Ia contacts was not
coextensive with the radially organized dendrites of
motoneurons: Dendrites oriented in the ventromedial to
dorsolateral axis had the fewest (8%) contacts, whereas
rostrocaudal dendrites had the most (63%) contacts.
Nevertheless, contacts were widely distributed on the
motoneuron surface, with few on and near the soma (< or = 200
microns radial distance from the soma) or on the most distal
parts of the tree (> or = 1,000 microns). The boutons in
individual contact systems also showed wide spatial and
estimated electrotonic distributions; only 3/24 systems had
all contact located within a restricted spatial/electrotonic
region. The relations between these anatomical results and
existing electrophysiological data on group Ia synaptic
potentials are discussed.. EC 1.11.1.-.
49. Burstein, R.; Falkowsky, O.; Borsook, D.; Strassman, A. Distinct
lateral and medial projections of the spinohypothalamic tract
of the rat. J-Comp-Neurol. 1996 Sep 30; 373(4): 549-74; ISSN:
0021-9967.
UNITED-STATES. We recently described a direct nociceptive
projection from the spinal cord to the hypothalamus in the rat.
Several electrophysiological studies of this projection
indicated that the axons of some spinohypothalamic tract
neurons (SHT) reach the hypothalamus either by a lateral or by
a medial route. The purpose of this study was to determine the
origin of all SHT neurons that reach the hypothalamus through
the lateral and the medial projections, and to investigate the
possibility of ablating the SHT without damaging other
important sensory and motor tracts by combining retrograde
tracing techniques with axonal ablation. As compared with
control cases, significant (P < .05) reductions in the number of
labeled SHT neurons were encountered, 26% in the ipsilateral
spinal cord following lesions of the medial projection, 67% in
the contralateral spinal cord following lesions of the lateral
projection, and 94% in both contra- and ipsilateral sides
following lesions of both the medial and lateral projections.
Bilateral lesions of the lateral projections had no effect on
the distribution of labeled neurons in the spinal cord and
dorsal column nuclei following injections of Fluoro-Gold (FG)
into the thalamus, and a small unilateral lesion of the lateral
projection reduced the ipsilateral labeling in the motor cortex
following injections of FG into the pyramidal decussation.
These findings suggest that most SHT neurons ascend through
the contralateral lateral projection and that less than half
continue in the medial projection to the ipsilateral side. They
also suggest a site that can be lesioned without affecting
other ascending sensory spinal pathways.
50. Burstein, R.; Falkowsky, O.; Borsook, D.; Strassman, A. Distinct
lateral and medial projections of the spinohypothalamic tract
of the rat. J-Comp-Neurol. 1996 Sep 30; 373(4): 549-74; ISSN:
0021-9967.
UNITED-STATES. We recently described a direct nociceptive
projection from the spinal cord to the hypothalamus in the rat.
Several electrophysiological studies of this projection
indicated that the axons of some spinohypothalamic tract
neurons (SHT) reach the hypothalamus either by a lateral or by
a medial route. The purpose of this study was to determine the
origin of all SHT neurons that reach the hypothalamus through
the lateral and the medial projections, and to investigate the
possibility of ablating the SHT without damaging other
important sensory and motor tracts by combining retrograde
tracing techniques with axonal ablation. As compared with
control cases, significant (P < .05) reductions in the number of
labeled SHT neurons were encountered, 26% in the ipsilateral
spinal cord following lesions of the medial projection, 67% in
the contralateral spinal cord following lesions of the lateral
projection, and 94% in both contra- and ipsilateral sides
following lesions of both the medial and lateral projections.
Bilateral lesions of the lateral projections had no effect on
the distribution of labeled neurons in the spinal cord and
dorsal column nuclei following injections of Fluoro-Gold (FG)
into the thalamus, and a small unilateral lesion of the lateral
projection reduced the ipsilateral labeling in the motor cortex
following injections of FG into the pyramidal decussation.
These findings suggest that most SHT neurons ascend through
the contralateral lateral projection and that less than half
continue in the medial projection to the ipsilateral side. They
also suggest a site that can be lesioned without affecting
other ascending sensory spinal pathways.
51. Carlton, S. M.; Hargett, G. L.; Coggeshall, R. E. Distribution of
glycine-immunoreactive profiles in the monkey spinal cord: a
light microscopic and ultrastructural study. J-Comp-Neurol.
1996 Aug 5; 371(4): 589-602; ISSN: 0021-9967.
UNITED-STATES. The present study analyzed the relationships
of glycine (GLY)-immunoreactive (-IR) and unlabeled profiles
in the primate spinal cord. Light microscopic analysis
demonstrated GLY-IR profiles in laminae III-VII, with fewer
labeled profiles in laminae I, II, VIII, IX and X. The dorsal part
of the lateral funiculus and the dorsal funiculus contained few
labeled axons, in contrast to all other areas of white matter,
which were heavily labeled. At the electron microscopic level,
GLY-IR terminals in monkeys contained mainly round, with
occasional pleomorphic, clear vesicles; however, F-type GLY-
IR terminals synapsing on motoneurons contained pleomorphic
vesicles. This seems to be an important species difference
because vesicles in GLY-IR terminals in rat and cat are
predominantly oval or elliptical. GLY-IR terminals synapsed on
unlabeled as well as GLY-IR cell bodies and dendrites. This is
morphological evidence that GLY may be both an inhibitor (GLY-
IR terminals synapse on and presumably inhibit non-GLY cell
bodies and dendrites) and a disinhibitor (GLY-IR terminals
synapse on and presumably inhibit other GLY elements) of
spinal activity. Also noteworthy was the conspicuous absence
of axoaxonic interactions involving GLY-IR terminals. A
related finding was that GLY profiles were always
postsynaptic, never presynaptic, to glomerular primary
afferent terminals. The functional implications would seem to
be that primary afferent input can activate the spinal GLY
system but that there is little GLY presynaptic control of
afferent input in monkeys. This is in contrast to rats and cats,
in which axoaxonic interactions involving GLY-IR terminals
have been observed and where it is common to find GLY-IR
terminals presynaptic to glomerular primary afferent
terminals.. 56-40-6.
52. Carlton, S. M.; Hargett, G. L.; Coggeshall, R. E. Distribution of
glycine-immunoreactive profiles in the monkey spinal cord: a
light microscopic and ultrastructural study. J-Comp-Neurol.
1996 Aug 5; 371(4): 589-602; ISSN: 0021-9967.
UNITED-STATES. The present study analyzed the relationships
of glycine (GLY)-immunoreactive (-IR) and unlabeled profiles
in the primate spinal cord. Light microscopic analysis
demonstrated GLY-IR profiles in laminae III-VII, with fewer
labeled profiles in laminae I, II, VIII, IX and X. The dorsal part
of the lateral funiculus and the dorsal funiculus contained few
labeled axons, in contrast to all other areas of white matter,
which were heavily labeled. At the electron microscopic level,
GLY-IR terminals in monkeys contained mainly round, with
occasional pleomorphic, clear vesicles; however, F-type GLY-
IR terminals synapsing on motoneurons contained pleomorphic
vesicles. This seems to be an important species difference
because vesicles in GLY-IR terminals in rat and cat are
predominantly oval or elliptical. GLY-IR terminals synapsed on
unlabeled as well as GLY-IR cell bodies and dendrites. This is
morphological evidence that GLY may be both an inhibitor (GLY-
IR terminals synapse on and presumably inhibit non-GLY cell
bodies and dendrites) and a disinhibitor (GLY-IR terminals
synapse on and presumably inhibit other GLY elements) of
spinal activity. Also noteworthy was the conspicuous absence
of axoaxonic interactions involving GLY-IR terminals. A
related finding was that GLY profiles were always
postsynaptic, never presynaptic, to glomerular primary
afferent terminals. The functional implications would seem to
be that primary afferent input can activate the spinal GLY
system but that there is little GLY presynaptic control of
afferent input in monkeys. This is in contrast to rats and cats,
in which axoaxonic interactions involving GLY-IR terminals
have been observed and where it is common to find GLY-IR
terminals presynaptic to glomerular primary afferent
terminals.. 56-40-6.
53. Celichowski, J.; Krutki, P.; Bichler, E. Axonal conduction velocity
of motor units of rat's medial gastrocnemius muscle. J-
Physiol-Paris. 1996; 90(2): 75-8; ISSN: 0928-4257.
FRANCE. Axonal conduction velocity and its relations to
different contractile properties of motor units of medial
gastrocnemius muscle were investigated in nine Wistar rats
anaesthetized with pentobarbitone. Functionally isolated
motor units were identified as slow (S), fast resistant (FR)
and fast fatigable (FF). Axons of S motor units conducted
significantly more slowly than of fast units, while there was
considerable overlap between conduction velocities measured
for FR and FF types. The mean values of conduction velocity
were 50.9 m/s for S, 68.9 m/s for FR and 71.3 m/s for FF type
motor units. Strong and significant negative correlation
between conduction velocity and contraction time as well as
half-relaxation time was demonstrated. However, only a weak
correlation between conduction velocity and twitch tension,
tetanic tension or fatigue index was found. The multiple
regression analysis revealed that the major factor to
determine conduction velocity was contraction time.
54. Celichowski, J.; Krutki, P.; Bichler, E. Axonal conduction velocity
of motor units of rat's medial gastrocnemius muscle. J-
Physiol-Paris. 1996; 90(2): 75-8; ISSN: 0928-4257.
FRANCE. Axonal conduction velocity and its relations to
different contractile properties of motor units of medial
gastrocnemius muscle were investigated in nine Wistar rats
anaesthetized with pentobarbitone. Functionally isolated
motor units were identified as slow (S), fast resistant (FR)
and fast fatigable (FF). Axons of S motor units conducted
significantly more slowly than of fast units, while there was
considerable overlap between conduction velocities measured
for FR and FF types. The mean values of conduction velocity
were 50.9 m/s for S, 68.9 m/s for FR and 71.3 m/s for FF type
motor units. Strong and significant negative correlation
between conduction velocity and contraction time as well as
half-relaxation time was demonstrated. However, only a weak
correlation between conduction velocity and twitch tension,
tetanic tension or fatigue index was found. The multiple
regression analysis revealed that the major factor to
determine conduction velocity was contraction time.
55. Chernoff, E. A. Spinal cord regeneration: a phenomenon unique to
urodeles? Int-J-Dev-Biol. 1996 Aug; 40(4): 823-31; ISSN:
0214-6282.
SPAIN. Studies of neuronal survival and axonal regeneration in
birds and mammals have made it clear that the
microenvironment of the CNS is critical to the failure of CNS
regeneration in these animals. This environment includes
growth and trophic factors, ECM components and matrix
turnover enzymes, cytokines and other immune system
contributions. Urodele amphibians (salamanders and newts)
can regenerate spinal cord even as adults, and environmental
contributions of glial populations are a major part of the
difference between urodele and higher vertebrate spinal cord
regeneration. In particular, the behavior of injury-reactive
ependymal cells (radial glia) is critical to the regenerative
capacity of urodele spinal cord. In this review we examine
what is known about cell-cell interactions between ependymal
cells and neurons and between ependymal cells and other glial
populations. The known contributions of ependymal cell
products such as matrix metalloproteinases and trophic
factors are discussed. There is evidence in the literature that
an ependymal response occurs during embryonic or fetal
development in birds and mammals following spinal cord
transection, and this review discusses the implications of
such a process for future studies of spinal cord injury.. 0; 0.
56. Chernoff, E. A. Spinal cord regeneration: a phenomenon unique to
urodeles? Int-J-Dev-Biol. 1996 Aug; 40(4): 823-31; ISSN:
0214-6282.
SPAIN. Studies of neuronal survival and axonal regeneration in
birds and mammals have made it clear that the
microenvironment of the CNS is critical to the failure of CNS
regeneration in these animals. This environment includes
growth and trophic factors, ECM components and matrix
turnover enzymes, cytokines and other immune system
contributions. Urodele amphibians (salamanders and newts)
can regenerate spinal cord even as adults, and environmental
contributions of glial populations are a major part of the
difference between urodele and higher vertebrate spinal cord
regeneration. In particular, the behavior of injury-reactive
ependymal cells (radial glia) is critical to the regenerative
capacity of urodele spinal cord. In this review we examine
what is known about cell-cell interactions between ependymal
cells and neurons and between ependymal cells and other glial
populations. The known contributions of ependymal cell
products such as matrix metalloproteinases and trophic
factors are discussed. There is evidence in the literature that
an ependymal response occurs during embryonic or fetal
development in birds and mammals following spinal cord
transection, and this review discusses the implications of
such a process for future studies of spinal cord injury.. 0; 0.
57. Chiba, T.; Tanaka, K.; Tatsuoka, H.; Dun, S. L.; Dun, N. J. The
synaptic structure of PACAP immunoreactive axons in the
intermediolateral nucleus of the rat. Neurosci-Lett. 1996 Aug
16; 214(1): 65-8; ISSN: 0304-3940.
IRELAND. Immuno-electronmicroscopic studies were
performed to detect the presence and features of synaptic
contacts between pituitary adenylate cyclase activating
polypeptide immunoreactive (PACAP-ir) axons and cholera
toxin B-horseradish peroxidase labeled preganglionic
sympathetic neurons (PSNs) in the intermediolateral nucleus
of the rat thoracic spinal cord. PACAP-ir axon varicosities,
which contained small clear and large core synaptic vesicles,
were found to form asymmetric type of synaptic contacts with
dendrites and infrequently with somata of labeled
preganglionic neurons. The present study provides
ultrastructural evidence of PACAP-ir synaptic contacts with
PSNs, raising the possibility that the peptide may function as
a transmitter/modulator to these neurons.. 0; 0.
58. Chiba, T.; Tanaka, K.; Tatsuoka, H.; Dun, S. L.; Dun, N. J. The
synaptic structure of PACAP immunoreactive axons in the
intermediolateral nucleus of the rat. Neurosci-Lett. 1996 Aug
16; 214(1): 65-8; ISSN: 0304-3940.
IRELAND. Immuno-electronmicroscopic studies were
performed to detect the presence and features of synaptic
contacts between pituitary adenylate cyclase activating
polypeptide immunoreactive (PACAP-ir) axons and cholera
toxin B-horseradish peroxidase labeled preganglionic
sympathetic neurons (PSNs) in the intermediolateral nucleus
of the rat thoracic spinal cord. PACAP-ir axon varicosities,
which contained small clear and large core synaptic vesicles,
were found to form asymmetric type of synaptic contacts with
dendrites and infrequently with somata of labeled
preganglionic neurons. The present study provides
ultrastructural evidence of PACAP-ir synaptic contacts with
PSNs, raising the possibility that the peptide may function as
a transmitter/modulator to these neurons.. 0; 0.
59. Chizh, B. A.; Headley, P. M. Thyrotropin-releasing hormone
facilitates spinal nociceptive responses by potentiating NMDA
receptor-mediated transmission. Eur-J-Pharmacol. 1996 Apr
11; 300(3): 183-9; ISSN: 0014-2999.
NETHERLANDS. The interaction of thyrotropin-releasing
hormone (TRH) with NMDA receptor-mediated responses has
been investigated in alpha-chloralose-anaesthetized
spinalized rats with respect to its relevance to spinal
nociceptive transmission. The effects of TRH and of the
uncompetitive NMDA antagonist ketamine were tested on
responses of dorsal horn wide dynamic range neurones to
noxious pinch, heat and electrical stimuli in parallel with
those to iontophoretically applied N-methyl-D-aspartate
(NMDA) and AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-
4-propionic acid). Tests with NMDA blocking doses of ketamine
(4 mg/kg i.v.) demonstrated a variable NMDA receptor-
mediated component of all synaptic responses. TRH (0.5-1
mg/kg i.v.) enhanced the responses to NMDA (but not AMPA) in
parallel with an increase of responses to all noxious stimuli
and the 'wind-up' component of the responses to repeated
electrical stimulation. This potentiation was completely
reversed by a subsequent administration of ketamine (4 mg/kg
i.v.). The results indicate that TRH facilitates nociceptive
transmission in the spinal dorsal horn via a selective positive
modulation of NMDA receptor-mediated transmission.. 0; 0;
24305-27-9; 6384-92-5; 6740-88-1; 77521-29-0.
60. Chizh, B. A.; Headley, P. M. Thyrotropin-releasing hormone
facilitates spinal nociceptive responses by potentiating NMDA
receptor-mediated transmission. Eur-J-Pharmacol. 1996 Apr
11; 300(3): 183-9; ISSN: 0014-2999.
NETHERLANDS. The interaction of thyrotropin-releasing
hormone (TRH) with NMDA receptor-mediated responses has
been investigated in alpha-chloralose-anaesthetized
spinalized rats with respect to its relevance to spinal
nociceptive transmission. The effects of TRH and of the
uncompetitive NMDA antagonist ketamine were tested on
responses of dorsal horn wide dynamic range neurones to
noxious pinch, heat and electrical stimuli in parallel with
those to iontophoretically applied N-methyl-D-aspartate
(NMDA) and AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-
4-propionic acid). Tests with NMDA blocking doses of ketamine
(4 mg/kg i.v.) demonstrated a variable NMDA receptor-
mediated component of all synaptic responses. TRH (0.5-1
mg/kg i.v.) enhanced the responses to NMDA (but not AMPA) in
parallel with an increase of responses to all noxious stimuli
and the 'wind-up' component of the responses to repeated
electrical stimulation. This potentiation was completely
reversed by a subsequent administration of ketamine (4 mg/kg
i.v.). The results indicate that TRH facilitates nociceptive
transmission in the spinal dorsal horn via a selective positive
modulation of NMDA receptor-mediated transmission.. 0; 0;
24305-27-9; 6384-92-5; 6740-88-1; 77521-29-0.
61. Cohen, A. H.; Guan, L.; Harris, J.; Jung, R.; Kiemel, T. Interaction
between the caudal brainstem and the lamprey central pattern
generator for locomotion. Neuroscience. 1996 Oct; 74(4):
1161-73; ISSN: 0306-4522.
UNITED-STATES. Because of its remarkable simplicity and the
robustness of the isolated preparation, the lamprey has been
used as a model system to study locomotion and its central
pattern generator. The function of the spinal cord is relatively
well understood in this context, but the role of the brain or
even the caudal brainstem remains less so. We here present a
study of the interaction between the caudal brainstem and the
spinal pattern generator for locomotion. We show that the
interaction is highly complex, with both feedforward input
from the brainstem to spinal cord and feedback input from the
spinal cord to brainstem playing a significant role in the
motor output during locomotion. The brainstem, when diffusely
stimulated pharmacologically, can initiate fictive locomotion,
or it can disrupt or alter the ongoing D-glutamate initiated
motor output. The nature of the disruptions vary greatly, and
can induce generalized irregularity, while the alterations can
include accelerating or decelerating of the bursting. All
behaviors are displayed with spectrograms of the motor nerve
discharge. We also show that the unstimulated brainstem can
disrupt as well as slow the bursting, but in a complex fashion.
Finally, a slow episodic behavior initiated from the caudal
brainstem is also described. This can be elicited either by D-
glutamate to the brainstem or by ascending activity from the
spinal cord pattern generator. Thus, we demonstrate that the
interaction between the brainstem and the spinal cord during
the production of locomotion is highly complex. The locomotion
that is exhibited by the combined brainstem-spinal cord
preparation is extremely variable. This is in striking contrast
to the variability of the locomotor output pharmacologically
induced in the spinal cord alone. The latter preparation
exhibits remarkable regularity, or upon occasion, irregularity,
but not the routine irregularity or the systemic up and down
changes in frequency seen with the brainstem present.
However, the pattern of frequency changes induced by the
brainstem is not predictable, and remains to be understood.
62. Cohen, A. H.; Guan, L.; Harris, J.; Jung, R.; Kiemel, T. Interaction
between the caudal brainstem and the lamprey central pattern
generator for locomotion. Neuroscience. 1996 Oct; 74(4):
1161-73; ISSN: 0306-4522.
UNITED-STATES. Because of its remarkable simplicity and the
robustness of the isolated preparation, the lamprey has been
used as a model system to study locomotion and its central
pattern generator. The function of the spinal cord is relatively
well understood in this context, but the role of the brain or
even the caudal brainstem remains less so. We here present a
study of the interaction between the caudal brainstem and the
spinal pattern generator for locomotion. We show that the
interaction is highly complex, with both feedforward input
from the brainstem to spinal cord and feedback input from the
spinal cord to brainstem playing a significant role in the
motor output during locomotion. The brainstem, when diffusely
stimulated pharmacologically, can initiate fictive locomotion,
or it can disrupt or alter the ongoing D-glutamate initiated
motor output. The nature of the disruptions vary greatly, and
can induce generalized irregularity, while the alterations can
include accelerating or decelerating of the bursting. All
behaviors are displayed with spectrograms of the motor nerve
discharge. We also show that the unstimulated brainstem can
disrupt as well as slow the bursting, but in a complex fashion.
Finally, a slow episodic behavior initiated from the caudal
brainstem is also described. This can be elicited either by D-
glutamate to the brainstem or by ascending activity from the
spinal cord pattern generator. Thus, we demonstrate that the
interaction between the brainstem and the spinal cord during
the production of locomotion is highly complex. The locomotion
that is exhibited by the combined brainstem-spinal cord
preparation is extremely variable. This is in striking contrast
to the variability of the locomotor output pharmacologically
induced in the spinal cord alone. The latter preparation
exhibits remarkable regularity, or upon occasion, irregularity,
but not the routine irregularity or the systemic up and down
changes in frequency seen with the brainstem present.
However, the pattern of frequency changes induced by the
brainstem is not predictable, and remains to be understood.
63. Colin, I.; Rostaing, P.; Triller, A. Gephyrin accumulates at specific
plasmalemma loci during neuronal maturation in vitro. J-
Comp-Neurol. 1996 Oct 21; 374(3): 467-79; ISSN: 0021-9967.
UNITED-STATES. The distribution of glycine receptor (GlyR)-
associated gephyrin has been investigated in rat spinal cord
neurons maintained in vitro by means of immunocytochemical
techniques. Gephyrin, which is crucial for the stabilization of
postsynaptic GlyR microdomains, is present in mature neurons
at postsynaptic differentiations. With immunofluorescence,
discontinuous patches of gephyrin were detected within the
neuronal soma of spinal cord neurons on the 1st day after
plating. Subsequently, gephyrin was present at membrane
areas that correspond to points of contact between cells or
with the culture dish. By the 5th day, gephrin was mostly
associated with the MAP2-positive somatodendritic
compartment. With immunoelectron microscopy, gephyrin blobs
detected at the earliest stages (1-3 days after plating) were
found within the cytoplasm or associated with the plasma
membrane. Asymmetrically immunostained intercellular
contacts were only detected after 5 days, and gephyrin was
found in association with clearly differentiated postsynaptic
membranes at 7 days. At later stages, we observed gephyrin
immunoreactivity only at some synapses. Our results suggest
that gephyrin accumulates initially at the locus of cell-to-cell
contacts involved in adhesion processes. These localizations
may define hot spots for later accumulation of the GlyR and
possibly other receptors.. 0; 0; 0; 0; 0.
64. Colin, I.; Rostaing, P.; Triller, A. Gephyrin accumulates at specific
plasmalemma loci during neuronal maturation in vitro. J-
Comp-Neurol. 1996 Oct 21; 374(3): 467-79; ISSN: 0021-9967.
UNITED-STATES. The distribution of glycine receptor (GlyR)-
associated gephyrin has been investigated in rat spinal cord
neurons maintained in vitro by means of immunocytochemical
techniques. Gephyrin, which is crucial for the stabilization of
postsynaptic GlyR microdomains, is present in mature neurons
at postsynaptic differentiations. With immunofluorescence,
discontinuous patches of gephyrin were detected within the
neuronal soma of spinal cord neurons on the 1st day after
plating. Subsequently, gephyrin was present at membrane
areas that correspond to points of contact between cells or
with the culture dish. By the 5th day, gephrin was mostly
associated with the MAP2-positive somatodendritic
compartment. With immunoelectron microscopy, gephyrin blobs
detected at the earliest stages (1-3 days after plating) were
found within the cytoplasm or associated with the plasma
membrane. Asymmetrically immunostained intercellular
contacts were only detected after 5 days, and gephyrin was
found in association with clearly differentiated postsynaptic
membranes at 7 days. At later stages, we observed gephyrin
immunoreactivity only at some synapses. Our results suggest
that gephyrin accumulates initially at the locus of cell-to-cell
contacts involved in adhesion processes. These localizations
may define hot spots for later accumulation of the GlyR and
possibly other receptors.. 0; 0; 0; 0; 0.
65. Croom, J. E.; Barron, K. W.; Chandler, M. J.; Foreman, R. D.
Cutaneous blood flow increases in the rat hindpaw during
dorsal column stimulation. Brain-Res. 1996 Jul 29; 728(2):
281-6; ISSN: 0006-8993.
NETHERLANDS. The purpose of this study was to determine the
optimal stimulation site and parameters that result in the
greatest changes in cutaneous blood flow during dorsal column
stimulation (DCS). Laser Doppler flowmetry was used to
assess cutaneous blood flow changes in both rat hindpaws
during DCS with a unipolar ball electrode. We found that
stimulating the dorsal column at the L2 spinal segment at 0.6
mA at either 25 or 50 Hz with a pulse duration of 0.2 ms
resulted in the largest cutaneous blood flow increases in the
rat hindpaw. In addition, the DCS response appeared to be
limited primarily to the hindpaw ipsilateral to the site of DCS.
66. Croom, J. E.; Barron, K. W.; Chandler, M. J.; Foreman, R. D.
Cutaneous blood flow increases in the rat hindpaw during
dorsal column stimulation. Brain-Res. 1996 Jul 29; 728(2):
281-6; ISSN: 0006-8993.
NETHERLANDS. The purpose of this study was to determine the
optimal stimulation site and parameters that result in the
greatest changes in cutaneous blood flow during dorsal column
stimulation (DCS). Laser Doppler flowmetry was used to
assess cutaneous blood flow changes in both rat hindpaws
during DCS with a unipolar ball electrode. We found that
stimulating the dorsal column at the L2 spinal segment at 0.6
mA at either 25 or 50 Hz with a pulse duration of 0.2 ms
resulted in the largest cutaneous blood flow increases in the
rat hindpaw. In addition, the DCS response appeared to be
limited primarily to the hindpaw ipsilateral to the site of DCS.
67. Crowe, M. J.; Bresnahan, J. C.; Shuman, S. L.; Masters, J. N.; Beattie,
M. S. Apoptosis and delayed degeneration after spinal cord
injury in rats and monkeys. Nat-Med. 1997 Jan; 3(1): 73-6;
ISSN: 1078-8956.
UNITED-STATES. Apoptosis is a morphologically defined form
of programmed cell death seen in a variety of circumstances,
including immune cell selection, carcinogenesis and
development. Apoptosis has very recently been seen after
ischemic or traumatic injury to the central nervous system
(CNS), suggesting that active cell death as well as passive
necrosis may mediate damage after CNS injury. After spinal
cord injury (SCI) in the rat, typical post-traumatic necrosis
occurred, but in addition, apoptotic cells were found from 6
hours to 3 weeks after injury, especially in the spinal white
matter. Apoptotic cells were positive for oligodendrocyte
markers. After SCI in monkeys, apoptotic cells were found
within remote degenerating fiber tracts. Both secondary
degeneration at the site of SCI and the chronic demyelination
of tracts away from the injury appear to be due in part to
apoptosis. As cytokines have been shown to mediate
oligodendrocyte death in vitro, it seems likely that chronic
demyelination after CNS injury shares features with chronic
degenerative disorders like multiple sclerosis.
68. Crowe, M. J.; Bresnahan, J. C.; Shuman, S. L.; Masters, J. N.; Beattie,
M. S. Apoptosis and delayed degeneration after spinal cord
injury in rats and monkeys. Nat-Med. 1997 Jan; 3(1): 73-6;
ISSN: 1078-8956.
UNITED-STATES. Apoptosis is a morphologically defined form
of programmed cell death seen in a variety of circumstances,
including immune cell selection, carcinogenesis and
development. Apoptosis has very recently been seen after
ischemic or traumatic injury to the central nervous system
(CNS), suggesting that active cell death as well as passive
necrosis may mediate damage after CNS injury. After spinal
cord injury (SCI) in the rat, typical post-traumatic necrosis
occurred, but in addition, apoptotic cells were found from 6
hours to 3 weeks after injury, especially in the spinal white
matter. Apoptotic cells were positive for oligodendrocyte
markers. After SCI in monkeys, apoptotic cells were found
within remote degenerating fiber tracts. Both secondary
degeneration at the site of SCI and the chronic demyelination
of tracts away from the injury appear to be due in part to
apoptosis. As cytokines have been shown to mediate
oligodendrocyte death in vitro, it seems likely that chronic
demyelination after CNS injury shares features with chronic
degenerative disorders like multiple sclerosis.
69. Crutcher, K. A.; Humbertson, AO Jr; Martin, G. F. The origin of
brainstem-spinal pathways in the North American opossum
(Didelphis virginiana). Studies using the horseradish
peroxidase method. J-Comp-Neurol. 1978 May 1; 179(1): 169-
93; ISSN: 0021-9967.
UNITED-STATES. EC 1.11.1.-.
70. Crutcher, K. A.; Humbertson, AO Jr; Martin, G. F. The origin of
brainstem-spinal pathways in the North American opossum
(Didelphis virginiana). Studies using the horseradish
peroxidase method. J-Comp-Neurol. 1978 May 1; 179(1): 169-
93; ISSN: 0021-9967.
UNITED-STATES. EC 1.11.1.-.
71. Cueva Rolon, R.; Sansone, G.; Bianca, R.; Gomez, L. E.; Beyer, C.;
Whipple, B.; Komisaruk, B. R. Vagotomy blocks responses to
vaginocervical stimulation after genitospinal neurectomy in
rats. Physiol-Behav. 1996 Jul; 60(1): 19-24; ISSN: 0031-9384.
UNITED-STATES. To ascertain whether any effects of
vaginocervical stimulation (VS) are mediated by the vagus
nerve, all known afferent nerves from the reproductive tract
to the spinal cord were transected and the rats were tested
for residual responses to VS. After combined bilateral
transection of the pelvic, hypogastric, and pudendal nerves
(NX), the following responses to VS were greatly reduced or
abolished: lordosis to flank-perineum palpation, leg extension,
immobilization, and blockage of both tail withdrawal to
radiant heat and leg withdrawal to foot pinch. However, after
these nerve cuts, the following persisted as significant
residual responses to VS: 1) analgesia [measured as increase
in vocalization threshold (VOCT) to tailshock], 2) pupil
dilatation (PD), and 3) increase in heart rate (HR). Subsequent
bilateral subdiaphragmatic vagotomy (VX) significantly
reduced the magnitude of PD and abolished the analgesia. By
contrast, VX produced no significant effect on the HR increase
to VS. The above findings provide evidence that brain-mediated
responses to vaginocervical stimulation can be elicited via the
vagus nerves.
72. Cueva Rolon, R.; Sansone, G.; Bianca, R.; Gomez, L. E.; Beyer, C.;
Whipple, B.; Komisaruk, B. R. Vagotomy blocks responses to
vaginocervical stimulation after genitospinal neurectomy in
rats. Physiol-Behav. 1996 Jul; 60(1): 19-24; ISSN: 0031-9384.
UNITED-STATES. To ascertain whether any effects of
vaginocervical stimulation (VS) are mediated by the vagus
nerve, all known afferent nerves from the reproductive tract
to the spinal cord were transected and the rats were tested
for residual responses to VS. After combined bilateral
transection of the pelvic, hypogastric, and pudendal nerves
(NX), the following responses to VS were greatly reduced or
abolished: lordosis to flank-perineum palpation, leg extension,
immobilization, and blockage of both tail withdrawal to
radiant heat and leg withdrawal to foot pinch. However, after
these nerve cuts, the following persisted as significant
residual responses to VS: 1) analgesia [measured as increase
in vocalization threshold (VOCT) to tailshock], 2) pupil
dilatation (PD), and 3) increase in heart rate (HR). Subsequent
bilateral subdiaphragmatic vagotomy (VX) significantly
reduced the magnitude of PD and abolished the analgesia. By
contrast, VX produced no significant effect on the HR increase
to VS. The above findings provide evidence that brain-mediated
responses to vaginocervical stimulation can be elicited via the
vagus nerves.
73. Cumberbatch, M. J.; Herrero, J. F.; Headley, P. M. Studies of
synaptic transmission in vivo: indirect versus direct effects
of (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-
propionic acid/kainate antagonists on rat spinal sensory
responses. Neurosci-Lett. 1996 Feb 2; 204(1-2): 33-6; ISSN:
0304-3940.
IRELAND. The (RS)-alpha-amino-3-hydroxy-5-methyl-4-
isoxazole-propionic acid (AMPA)/kainate receptor antagonists
2,3-dihydroxy-6-nitro-7-sulfamoylbenzo[f]quinoxaline (NBQX)
and 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX) were
examined by microiontophoretic administration in
electrophysiological tests on spinal neurones in alpha-
chloralose anaesthetized rats. The antagonists significantly
reduced extracellularly recorded nociceptive and non-
nociceptive responses, as expected; concurrently they reduced
background discharge. When the background discharge rate was
held constant, the antagonists no longer significantly reduced
the evoked responses. This indicates that in the absence of
such control, the antagonists decreased cell excitability and
only indirectly affected the test responses. Unless such
indirect effects have been controlled for, the interpretation of
the actions of AMPA/kainate antagonists on evoked synaptic
responses is compromised and may be erroneous.. 0; 0; 0; 0; 0;
115066-14-3; 118876-58-7; 6384-92-5.
74. Cumberbatch, M. J.; Herrero, J. F.; Headley, P. M. Studies of
synaptic transmission in vivo: indirect versus direct effects
of (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole-
propionic acid/kainate antagonists on rat spinal sensory
responses. Neurosci-Lett. 1996 Feb 2; 204(1-2): 33-6; ISSN:
0304-3940.
IRELAND. The (RS)-alpha-amino-3-hydroxy-5-methyl-4-
isoxazole-propionic acid (AMPA)/kainate receptor antagonists
2,3-dihydroxy-6-nitro-7-sulfamoylbenzo[f]quinoxaline (NBQX)
and 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX) were
examined by microiontophoretic administration in
electrophysiological tests on spinal neurones in alpha-
chloralose anaesthetized rats. The antagonists significantly
reduced extracellularly recorded nociceptive and non-
nociceptive responses, as expected; concurrently they reduced
background discharge. When the background discharge rate was
held constant, the antagonists no longer significantly reduced
the evoked responses. This indicates that in the absence of
such control, the antagonists decreased cell excitability and
only indirectly affected the test responses. Unless such
indirect effects have been controlled for, the interpretation of
the actions of AMPA/kainate antagonists on evoked synaptic
responses is compromised and may be erroneous.. 0; 0; 0; 0; 0;
115066-14-3; 118876-58-7; 6384-92-5.
75. Curtis, D. R.; Gynther, B. D.; Beattie, D. T.; Lacey, G. An in vivo
electrophysiological investigation of group Ia afferent fibres
and ventral horn terminations in the cat spinal cord. Exp-
Brain-Res. 1995; 106(3): 403-17; ISSN: 0014-4819.
GERMANY. An extracellular microstimulation technique has
been used to investigate and compare the properties of group I
primary afferent myelinated fibres in the dorsal column and
group Ia unmyelinated terminations in the lumbar spinal cord
of cats anaesthetised with pentobarbitone sodium. Fibres were
distinguished from terminations on the basis of location,
anodic blocking factor and sensitivity to GABAA mimetics. The
recovery curves of threshold following an orthodromic impulse
provided an estimate of both action potential duration and rate
of repolarization. The action potentials of group Ia
terminations were of briefer duration (by a factor of
approximately 2) with more rapid rates of repolarization
(factor of approximately 3) than those of the myelinated
fibres. The prolongation of termination but not fibre action
potentials by microelectrophoretic tetraethylammonium and
4-aminopyridine indicated the presence of voltage-activated
potassium channels in the termination membrane. Differences
in the effects on Ia termination action potentials of
depolarizations (reductions in threshold) associated with a
preceding action potential, synaptically released GABA,
microelectrophoretic piperidine-4-sulphonic acid or DL-
homocysteic acid suggest that an increase in termination
membrane conductance is the major factor in the reduction of
transmitter release during the activation of presynaptic
GABAA receptors.. 0; 504-24-5; 59-46-1; 66-40-0.
76. Curtis, D. R.; Gynther, B. D.; Beattie, D. T.; Lacey, G. An in vivo
electrophysiological investigation of group Ia afferent fibres
and ventral horn terminations in the cat spinal cord. Exp-
Brain-Res. 1995; 106(3): 403-17; ISSN: 0014-4819.
GERMANY. An extracellular microstimulation technique has
been used to investigate and compare the properties of group I
primary afferent myelinated fibres in the dorsal column and
group Ia unmyelinated terminations in the lumbar spinal cord
of cats anaesthetised with pentobarbitone sodium. Fibres were
distinguished from terminations on the basis of location,
anodic blocking factor and sensitivity to GABAA mimetics. The
recovery curves of threshold following an orthodromic impulse
provided an estimate of both action potential duration and rate
of repolarization. The action potentials of group Ia
terminations were of briefer duration (by a factor of
approximately 2) with more rapid rates of repolarization
(factor of approximately 3) than those of the myelinated
fibres. The prolongation of termination but not fibre action
potentials by microelectrophoretic tetraethylammonium and
4-aminopyridine indicated the presence of voltage-activated
potassium channels in the termination membrane. Differences
in the effects on Ia termination action potentials of
depolarizations (reductions in threshold) associated with a
preceding action potential, synaptically released GABA,
microelectrophoretic piperidine-4-sulphonic acid or DL-
homocysteic acid suggest that an increase in termination
membrane conductance is the major factor in the reduction of
transmitter release during the activation of presynaptic
GABAA receptors.. 0; 504-24-5; 59-46-1; 66-40-0.
77. Dacko, S. M.; Sokoloff, A. J.; Cope, T. C. Recruitment of triceps
surae motor units in the decerebrate cat. I. Independence of
type S units in soleus and medial gastrocnemius muscles. J-
Neurophysiol. 1996 May; 75(5): 1997-2004; ISSN: 0022-3077.
UNITED-STATES. 1. We tested the hypothesis that reflex
inhibition of soleus motor units reflects selective inhibition
of slow-twitch (type S) motor units throughout the triceps
surae. Physiological properties including type, together with
firing behavior, were measured from single motor units in the
medial gastrocnemius (MG) muscle of decerebrate cats with
the use of intra-axonal recording and stimulation. MG unit
firing was contrasted during net inhibition or excitation of the
slow-twitch soleus muscle produced by ramp-hold-release
stretches of MG. 2. Stretch of the MG muscle increased the
firing of type S motor units in the MG regardless of the reflex
response of the soleus muscle. When stretch inhibited soleus,
each of the 14 type S units sampled from MG either was newly
recruited or exhibited increases in the rate of ongoing firing.
Increased firing was observed in 320 of 321 stretch trials. For
8 of these 14 units, a total of 155 stretch trials evoked reflex
excitation of soleus, and unit firing increased in all trials. 3.
For the eight MG type S motor units studied during both reflex
inhibition and excitation of soleus, firing rate tended to be
higher during inhibition. The higher rates were also associated
with the higher MG forces required to elicit soleus inhibition.
For one MG type S unit it was possible to compare firing rates
during soleus inhibition and excitation for trials of
overlapping levels of MG force. For this unit, firing rate was
similar, but still appreciably higher, during inhibition. 4.
Soleus inhibition was also produced by stretch of the plantaris
(PL) or lateral gastrocnemius (LG) muscles. Type S units in PL
(n = 2) or in LG (n = 1) were recruited or increased firing rate
even when stretch of these muscles produced soleus inhibition.
5. The firing behavior of 12 fast-twitch (type F) units was
studied (11 from MG, 1 from PL). All type F units either were
recruited or accelerated the rate of firing during soleus
inhibition, as well as during soleus excitation. 6. These
findings give evidence that reflex inhibition of type S motor
units in the soleus muscle does not necessarily reflect an
organizational scheme in which there is inactivation of type S
units in other active muscles. In the DISCUSSION we point out
the absence of direct evidence for selective inactivation of
units on the basis of their type classification.
78. Dacko, S. M.; Sokoloff, A. J.; Cope, T. C. Recruitment of triceps
surae motor units in the decerebrate cat. I. Independence of
type S units in soleus and medial gastrocnemius muscles. J-
Neurophysiol. 1996 May; 75(5): 1997-2004; ISSN: 0022-3077.
UNITED-STATES. 1. We tested the hypothesis that reflex
inhibition of soleus motor units reflects selective inhibition
of slow-twitch (type S) motor units throughout the triceps
surae. Physiological properties including type, together with
firing behavior, were measured from single motor units in the
medial gastrocnemius (MG) muscle of decerebrate cats with
the use of intra-axonal recording and stimulation. MG unit
firing was contrasted during net inhibition or excitation of the
slow-twitch soleus muscle produced by ramp-hold-release
stretches of MG. 2. Stretch of the MG muscle increased the
firing of type S motor units in the MG regardless of the reflex
response of the soleus muscle. When stretch inhibited soleus,
each of the 14 type S units sampled from MG either was newly
recruited or exhibited increases in the rate of ongoing firing.
Increased firing was observed in 320 of 321 stretch trials. For
8 of these 14 units, a total of 155 stretch trials evoked reflex
excitation of soleus, and unit firing increased in all trials. 3.
For the eight MG type S motor units studied during both reflex
inhibition and excitation of soleus, firing rate tended to be
higher during inhibition. The higher rates were also associated
with the higher MG forces required to elicit soleus inhibition.
For one MG type S unit it was possible to compare firing rates
during soleus inhibition and excitation for trials of
overlapping levels of MG force. For this unit, firing rate was
similar, but still appreciably higher, during inhibition. 4.
Soleus inhibition was also produced by stretch of the plantaris
(PL) or lateral gastrocnemius (LG) muscles. Type S units in PL
(n = 2) or in LG (n = 1) were recruited or increased firing rate
even when stretch of these muscles produced soleus inhibition.
5. The firing behavior of 12 fast-twitch (type F) units was
studied (11 from MG, 1 from PL). All type F units either were
recruited or accelerated the rate of firing during soleus
inhibition, as well as during soleus excitation. 6. These
findings give evidence that reflex inhibition of type S motor
units in the soleus muscle does not necessarily reflect an
organizational scheme in which there is inactivation of type S
units in other active muscles. In the DISCUSSION we point out
the absence of direct evidence for selective inactivation of
units on the basis of their type classification.
79. Danziger, N.; Remy, P.; Pidoux, B.; Dormont, D.; Samson, Y.;
Fournier, E.; Wall, P. D.; Willer, J. C. A clinical and
neurophysiological study of a patient with an extensive
transection of the spinal cord sparing only a part of one
anterolateral quadrant. Brain. 1996 Dec; 119( Pt 6): 1835-48;
ISSN: 0006-8950.
ENGLAND. In 1976, Noordenbos and Wall studied sensory
functions in a woman with a surgically verified T3 spinal cord
transection which spared only a part of the left anterolateral
quadrant, We re-investigated this unique case 18 years after
the lesion and included a comparable sensory examination, MRI
of the spinal cord, somatosensory evoked potentials, PET-
activation study during hand and foot vibration and analysis of
flexion reflex modulation during the Jendrassik manoeuvre. Our
results show that the residual anterolateral quadrant contains
ascending pathways carrying a wide range of sensory
information as well as descending pathways modulating
flexion reflex activity at the spinal level. Moreover, the
changes in sensory functions and the unique pattern of cortical
activation suggest a functional reorganization of the
connectivity between the periphery and the cerebral cortex.
Changes of facilitation and/or of inhibition at different levels
of the somatosensory system may account for these longterm
plastic changes.
80. Danziger, N.; Remy, P.; Pidoux, B.; Dormont, D.; Samson, Y.;
Fournier, E.; Wall, P. D.; Willer, J. C. A clinical and
neurophysiological study of a patient with an extensive
transection of the spinal cord sparing only a part of one
anterolateral quadrant. Brain. 1996 Dec; 119( Pt 6): 1835-48;
ISSN: 0006-8950.
ENGLAND. In 1976, Noordenbos and Wall studied sensory
functions in a woman with a surgically verified T3 spinal cord
transection which spared only a part of the left anterolateral
quadrant, We re-investigated this unique case 18 years after
the lesion and included a comparable sensory examination, MRI
of the spinal cord, somatosensory evoked potentials, PET-
activation study during hand and foot vibration and analysis of
flexion reflex modulation during the Jendrassik manoeuvre. Our
results show that the residual anterolateral quadrant contains
ascending pathways carrying a wide range of sensory
information as well as descending pathways modulating
flexion reflex activity at the spinal level. Moreover, the
changes in sensory functions and the unique pattern of cortical
activation suggest a functional reorganization of the
connectivity between the periphery and the cerebral cortex.
Changes of facilitation and/or of inhibition at different levels
of the somatosensory system may account for these longterm
plastic changes.
81. Darian Smith, I.; Galea, M. P.; Darian Smith, C. Manual dexterity:
how does the cerebral cortex contribute? Clin-Exp-Pharmacol-
Physiol. 1996 Oct; 23(10-11): 948-56; ISSN: 0305-1870.
AUSTRALIA. 1. Manual dexterity, of great evolutionary
significance to the primates, ranges in complexity from the
precise opposition of finger and thumb to Brendal playing
Mozart. All dexterity depends on a sustained and rapid transfer
of sensorimotor information between the cerebral cortex and
the cervical spinal cord. 2. Multiple separate corticospinal
neuron populations originate from cortical areas four, the
supplementary motor area, anterior cingulate, postarcuate,
parietal and insular cortex. Each corticospinal neuron
population projects in parallel to all spinal segments, and has
a distinctive pattern of terminations. 3. Each corticospinal
neuron population has a unique thalamic input which can relay
particular sensorimotor information from the sense organs,
cerebellum and basal ganglia. The overall structural
framework of these sensorimotor pathways, with many
parallel corticospinal channels, with interconnections in the
cerebral cortex and spinal cord to enable crosstalk between
the channels, is that needed for parallel distributed
processing, which would enable the very rapid transfer of
information between the cerebral cortex and spinal cord
needed for any sophisticated use of the hand. 4. Hemisection of
the cervical spinal cord in the macaque results in an
immediate hemiplegia, with subsequent remarkable although
incomplete recovery of hand and finger movements. The only
direct corticospinal input to the hemicord caudal to the
hemisection, even after 3 years, is the approximately 10% of
fibres which cross the midline caudal to the lesion: the fibres
'spared' by the hemisection. A matching 'sparing' of
somatosensory input from the paresed limb also occurs. No
regeneration of the interrupted pathways has been visualized
using modern tracer techniques. 5. Cervical hemisection
permanently reduces the number of parallel channels which
transmit information between cortex and spinal cord, but does
not reduce their cortical origins nor the neuron populations
targeted in the spinal cord. We infer that the content of the
information that can be transmitted between the cortex and
spinal cord is not greatly changed, but the rate of
transmission of this information is sharply reduced, and is the
'bottleneck' that limits the complete recovery of dexterity
following hemisection. The remarkable recovery that does
occur presumably reflects more economic transmission of
information by the few spared channels. We guess that this
involves substantial synaptic reorganization not visualized by
the procedures we have used.
82. Darian Smith, I.; Galea, M. P.; Darian Smith, C. Manual dexterity:
how does the cerebral cortex contribute? Clin-Exp-Pharmacol-
Physiol. 1996 Oct; 23(10-11): 948-56; ISSN: 0305-1870.
AUSTRALIA. 1. Manual dexterity, of great evolutionary
significance to the primates, ranges in complexity from the
precise opposition of finger and thumb to Brendal playing
Mozart. All dexterity depends on a sustained and rapid transfer
of sensorimotor information between the cerebral cortex and
the cervical spinal cord. 2. Multiple separate corticospinal
neuron populations originate from cortical areas four, the
supplementary motor area, anterior cingulate, postarcuate,
parietal and insular cortex. Each corticospinal neuron
population projects in parallel to all spinal segments, and has
a distinctive pattern of terminations. 3. Each corticospinal
neuron population has a unique thalamic input which can relay
particular sensorimotor information from the sense organs,
cerebellum and basal ganglia. The overall structural
framework of these sensorimotor pathways, with many
parallel corticospinal channels, with interconnections in the
cerebral cortex and spinal cord to enable crosstalk between
the channels, is that needed for parallel distributed
processing, which would enable the very rapid transfer of
information between the cerebral cortex and spinal cord
needed for any sophisticated use of the hand. 4. Hemisection of
the cervical spinal cord in the macaque results in an
immediate hemiplegia, with subsequent remarkable although
incomplete recovery of hand and finger movements. The only
direct corticospinal input to the hemicord caudal to the
hemisection, even after 3 years, is the approximately 10% of
fibres which cross the midline caudal to the lesion: the fibres
'spared' by the hemisection. A matching 'sparing' of
somatosensory input from the paresed limb also occurs. No
regeneration of the interrupted pathways has been visualized
using modern tracer techniques. 5. Cervical hemisection
permanently reduces the number of parallel channels which
transmit information between cortex and spinal cord, but does
not reduce their cortical origins nor the neuron populations
targeted in the spinal cord. We infer that the content of the
information that can be transmitted between the cortex and
spinal cord is not greatly changed, but the rate of
transmission of this information is sharply reduced, and is the
'bottleneck' that limits the complete recovery of dexterity
following hemisection. The remarkable recovery that does
occur presumably reflects more economic transmission of
information by the few spared channels. We guess that this
involves substantial synaptic reorganization not visualized by
the procedures we have used.
83. Davis, J. A.; Reed, R. R. Role of Olf-1 and Pax-6 transcription
factors in neurodevelopment. J-Neurosci. 1996 Aug 15; 16(16):
5082-94; ISSN: 0270-6474.
UNITED-STATES. The Olf-1 transcription factor is expressed
in olfactory sensory neurons where it regulates the expression
of genes that encode components of the odorant signal
transduction cascade and contributes to the terminal
phenotype of these sensory neurons. We examined the pattern
of expression of Olf-1 protein during mouse embryogenesis and
observed Olf-1 expression transiently in a subset of neural
precursor cells in the CNS and peripheral nervous system. The
expression of Olf-1 protein was enriched in sensory
components and coincided with postmitotic cells and the
initiation of overt differentiation within the nervous system.
The spatial and temporal patterns of Olf-1 expression during
development suggest a role in neurogenesis that is common
among different neural cell types. In parallel, the expression
pattern of Pax-6, a transcription factor that is widely
expressed in the developing nervous system, including the
visual and olfactory systems, was examined with a C-terminal
antibody. In the retina, Pax-6 protein is detected in the lens,
the cornea, and the neural and pigmented retinas. In the
olfactory epithelium, Pax-6 protein is expressed exclusively
in cells of non-neuronal lineage, including sustentacular cells,
basal cells, and Bowman's glands. The nonoverlapping, cellular
localization patterns of Pax-6 and Olf-1 demarcate distinct
cell lineages within the developing olfactory epithelium.. 0; 0;
0; 0; 0.
84. Davis, J. A.; Reed, R. R. Role of Olf-1 and Pax-6 transcription
factors in neurodevelopment. J-Neurosci. 1996 Aug 15; 16(16):
5082-94; ISSN: 0270-6474.
UNITED-STATES. The Olf-1 transcription factor is expressed
in olfactory sensory neurons where it regulates the expression
of genes that encode components of the odorant signal
transduction cascade and contributes to the terminal
phenotype of these sensory neurons. We examined the pattern
of expression of Olf-1 protein during mouse embryogenesis and
observed Olf-1 expression transiently in a subset of neural
precursor cells in the CNS and peripheral nervous system. The
expression of Olf-1 protein was enriched in sensory
components and coincided with postmitotic cells and the
initiation of overt differentiation within the nervous system.
The spatial and temporal patterns of Olf-1 expression during
development suggest a role in neurogenesis that is common
among different neural cell types. In parallel, the expression
pattern of Pax-6, a transcription factor that is widely
expressed in the developing nervous system, including the
visual and olfactory systems, was examined with a C-terminal
antibody. In the retina, Pax-6 protein is detected in the lens,
the cornea, and the neural and pigmented retinas. In the
olfactory epithelium, Pax-6 protein is expressed exclusively
in cells of non-neuronal lineage, including sustentacular cells,
basal cells, and Bowman's glands. The nonoverlapping, cellular
localization patterns of Pax-6 and Olf-1 demarcate distinct
cell lineages within the developing olfactory epithelium.. 0; 0;
0; 0; 0.
85. De Heus, R. B.; Diegenbach, P. C.; Van Raamsdonk, W.; Roberts, B. L.
Changes in enzyme histochemical profiles of identified spinal
motoneurons of the European eel, Anguilla anguilla, following
cordotomy. Histochem-J. 1996 May; 28(5): 335-40; ISSN:
0018-2214.
ENGLAND. The enzyme histochemical profiles of glucose-6-
phosphate dehydrogenase (a marker of synthetic performance),
succinate dehydrogenase (an indicator of oxidative
metabolism), and NADH tetrazolium reductase (a marker of
overall neuronal activity) were determined for identified
white muscle motoneurons in six control and six cordotomized
cels. Images were digitized and mean integrated absorbances
obtained using appropriate hardware and software. For
motoneurons caudal to the transection site there was a
significant decrease in the mean absorbance value for NADH
tetrazolium reductases which declines from 0.28 a.u.
(arbitrary units) in control animals to 0.23 a.u. in
cordotomized animals. However, no significant changes were
detected in the activities of glucose-6-phosphate and
succinate dehydrogenases. The cross-sectional area of the
motoneuronal cell body was not affected by cordotomy. The
decrease by around 20% in overall neuronal activity, as
expressed by NADH tetrazolium reductase activity, might be
expected from the decline in body motility that follows
cordotomy. Changes in SDH and G6PDH activities would also be
expected to follow this surgery, but none were seen, perhaps
because they are compensated for by changes in neuronal
metabolism that result from deafferentation.. EC 1.1.1.49; EC
1.3.99.1; EC 1.6.-.
86. De Heus, R. B.; Diegenbach, P. C.; Van Raamsdonk, W.; Roberts, B. L.
Changes in enzyme histochemical profiles of identified spinal
motoneurons of the European eel, Anguilla anguilla, following
cordotomy. Histochem-J. 1996 May; 28(5): 335-40; ISSN:
0018-2214.
ENGLAND. The enzyme histochemical profiles of glucose-6-
phosphate dehydrogenase (a marker of synthetic performance),
succinate dehydrogenase (an indicator of oxidative
metabolism), and NADH tetrazolium reductase (a marker of
overall neuronal activity) were determined for identified
white muscle motoneurons in six control and six cordotomized
cels. Images were digitized and mean integrated absorbances
obtained using appropriate hardware and software. For
motoneurons caudal to the transection site there was a
significant decrease in the mean absorbance value for NADH
tetrazolium reductases which declines from 0.28 a.u.
(arbitrary units) in control animals to 0.23 a.u. in
cordotomized animals. However, no significant changes were
detected in the activities of glucose-6-phosphate and
succinate dehydrogenases. The cross-sectional area of the
motoneuronal cell body was not affected by cordotomy. The
decrease by around 20% in overall neuronal activity, as
expressed by NADH tetrazolium reductase activity, might be
expected from the decline in body motility that follows
cordotomy. Changes in SDH and G6PDH activities would also be
expected to follow this surgery, but none were seen, perhaps
because they are compensated for by changes in neuronal
metabolism that result from deafferentation.. EC 1.1.1.49; EC
1.3.99.1; EC 1.6.-.
87. Dekhuijzen, A. J.; Bagust, J. Analysis of neural bursting:
nonrhythmic and rhythmic activity in isolated spinal cord. J-
Neurosci-Methods. 1996 Aug; 67(2): 141-7; ISSN: 0165-0270.
NETHERLANDS. Neuronal firing recorded from primary
afferents and central spinal neurons in isolated mammalian
spinal cord in vitro was analyzed using interspike interval
histograms and Poincare maps (Return maps). Interspike
interval histograms described the time between two
successive spikes. However, Poincare maps represented the
interspike interval preceding a spike against the interspike
interval following the spike. The variability in firing of
neurons occurring naturally in different preparations was
explored. In a presumptive single central spinal neuron, the
firing pattern provided a single cluster. During bursting in a
presumptive single primary afferent, the Poincare maps
provided information on interburst intervals. Moreover,
lengthening and or shortening of interspike intervals within
bursts can be detected in the maps. The firing of a population
of neurons was modulated using a pharmacological
intervention with 4-aminopyridine and resulted in a complex
Poincare map.. 504-24-5.
88. Dekhuijzen, A. J.; Bagust, J. Analysis of neural bursting:
nonrhythmic and rhythmic activity in isolated spinal cord. J-
Neurosci-Methods. 1996 Aug; 67(2): 141-7; ISSN: 0165-0270.
NETHERLANDS. Neuronal firing recorded from primary
afferents and central spinal neurons in isolated mammalian
spinal cord in vitro was analyzed using interspike interval
histograms and Poincare maps (Return maps). Interspike
interval histograms described the time between two
successive spikes. However, Poincare maps represented the
interspike interval preceding a spike against the interspike
interval following the spike. The variability in firing of
neurons occurring naturally in different preparations was
explored. In a presumptive single central spinal neuron, the
firing pattern provided a single cluster. During bursting in a
presumptive single primary afferent, the Poincare maps
provided information on interburst intervals. Moreover,
lengthening and or shortening of interspike intervals within
bursts can be detected in the maps. The firing of a population
of neurons was modulated using a pharmacological
intervention with 4-aminopyridine and resulted in a complex
Poincare map.. 504-24-5.
89. Della Torre, G.; Lucchi, M. L.; Brunetti, O.; Pettorossi, V. E.;
Clavenzani, P.; Bortolami, R. Central projections and entries of
capsaicin-sensitive muscle afferents. Brain-Res. 1996 Mar 25;
713(1-2): 223-31; ISSN: 0006-8993.
NETHERLANDS. The entry pathway and central distribution of A
delta and C muscle afferents within the central nervous
system (CNS) were investigated by combining electron
microscopy and electrophysiological analysis after
intramuscular injection of capsaicin. The drug was injected
into the rat lateral gastrocnemius (LG) and extraocular (EO)
muscles. The compound action potentials of LG nerve and the
evoked field potentials recorded in semilunar ganglion showed
an immediate and permanent reduction in A delta and C
components. The morphological data revealed degenerating
unmyelinated axons and terminals in the inner sublamina II and
in the border of laminae I-II of the dorsal horn at L4-L5 and
C1-C2 (subnucleus caudalis trigemini) spinal cord segments.
Most degenerating terminals were the central bouton (C) of
type I and II synaptic glomeruli. Furthermore, degenerating
peripheral axonal endings (V2) presynaptic to normal C were
found. Since V2 were previously found degenerated after
cutting the oculomotor nerve (ON) or L4 ventral root, we
conclude that some A delta and C afferents from LG and EO
muscles entering the CNS by ON or ventral roots make
axoaxonic synapses on other primary afferents to promote an
afferent control of sensory input.. 404-86-4.
90. Della Torre, G.; Lucchi, M. L.; Brunetti, O.; Pettorossi, V. E.;
Clavenzani, P.; Bortolami, R. Central projections and entries of
capsaicin-sensitive muscle afferents. Brain-Res. 1996 Mar 25;
713(1-2): 223-31; ISSN: 0006-8993.
NETHERLANDS. The entry pathway and central distribution of A
delta and C muscle afferents within the central nervous
system (CNS) were investigated by combining electron
microscopy and electrophysiological analysis after
intramuscular injection of capsaicin. The drug was injected
into the rat lateral gastrocnemius (LG) and extraocular (EO)
muscles. The compound action potentials of LG nerve and the
evoked field potentials recorded in semilunar ganglion showed
an immediate and permanent reduction in A delta and C
components. The morphological data revealed degenerating
unmyelinated axons and terminals in the inner sublamina II and
in the border of laminae I-II of the dorsal horn at L4-L5 and
C1-C2 (subnucleus caudalis trigemini) spinal cord segments.
Most degenerating terminals were the central bouton (C) of
type I and II synaptic glomeruli. Furthermore, degenerating
peripheral axonal endings (V2) presynaptic to normal C were
found. Since V2 were previously found degenerated after
cutting the oculomotor nerve (ON) or L4 ventral root, we
conclude that some A delta and C afferents from LG and EO
muscles entering the CNS by ON or ventral roots make
axoaxonic synapses on other primary afferents to promote an
afferent control of sensory input.. 404-86-4.
91. DeRuiter, C. J.; De Haan, A.; Sargeant, A. J. Fast-twitch muscle
unit properties in different rat medial gastrocnemius muscle
compartments. J-Neurophysiol. 1996 Jun; 75(6): 2243-54;
ISSN: 0022-3077.
UNITED-STATES. 1. The effect of muscle unit (MU) localization
on physiological properties was investigated within the fast-
twitch fatigue-resistant (FR) and fast-fatigable (FF) MU
populations of rat medial gastrocnemius (MG) muscle. Single
MG MUs were functionally isolated by microdissection of the
ventral roots. FR and FF MU properties of the most proximal
and distal muscle compartments were compared. The most
proximal and distal compartment are subvolumes of the MG
innervated by the most proximal and distal primary nerve
branch, respectively. A subsample of the isolated units was
glycogen depleted and muscle cross sections were stained for
glycogen and myosin-adenosinetriphosphatase. 2. It was shown
that proximal FF and FR units reached optimum length for
force production at shorter muscle lengths compared with the
distal FR and FF units. 3. The fast MUs of the proximal
compartment had small territories that were located close to
and/or within the mixed region (containing type I, IIA, IIX, and
IIB fibers) of the muscle. The fast MUs of the distal
compartment had greater territories that were located in the
more superficial muscle part (containing only type IIX and IIB
fibers) and in some cases spanned the entire area of the distal
muscle compartment. 4. FR and FF MUs consisted of muscle
fibers identified histochemically as type IIX and IIB,
respectively. 5. Within each of the FR and FF MU populations,
MUs that were located in the most proximal muscle
compartment were more resistant to fatigue compared with
the units located in the most distal compartment. 6. Cross-
sectional fiber areas were smaller for the proximal FR and FF
fibers, but specific force did not differ among units.
Consequently, when account was taken of the innervation
ratio, the proximal FR and FF units produced less force than
distal units of the same type. Tetanic forces were 87 +/- 27
(SD) mN (proximal FR), 154 +/- 53 (SD) mN (distal FR), 142 +/-
25 (SD) mN (proximal FF), and 229 +/- 86 (SD) mN (distal FF).
7. The present findings suggest that with increasing demand
placed on rat MG during in vivo locomotion, recruitment is
likely to proceed from proximal to distal muscle parts within
the FR and FF MU populations.. 9005-79-2.
92. DeRuiter, C. J.; De Haan, A.; Sargeant, A. J. Fast-twitch muscle
unit properties in different rat medial gastrocnemius muscle
compartments. J-Neurophysiol. 1996 Jun; 75(6): 2243-54;
ISSN: 0022-3077.
UNITED-STATES. 1. The effect of muscle unit (MU) localization
on physiological properties was investigated within the fast-
twitch fatigue-resistant (FR) and fast-fatigable (FF) MU
populations of rat medial gastrocnemius (MG) muscle. Single
MG MUs were functionally isolated by microdissection of the
ventral roots. FR and FF MU properties of the most proximal
and distal muscle compartments were compared. The most
proximal and distal compartment are subvolumes of the MG
innervated by the most proximal and distal primary nerve
branch, respectively. A subsample of the isolated units was
glycogen depleted and muscle cross sections were stained for
glycogen and myosin-adenosinetriphosphatase. 2. It was shown
that proximal FF and FR units reached optimum length for
force production at shorter muscle lengths compared with the
distal FR and FF units. 3. The fast MUs of the proximal
compartment had small territories that were located close to
and/or within the mixed region (containing type I, IIA, IIX, and
IIB fibers) of the muscle. The fast MUs of the distal
compartment had greater territories that were located in the
more superficial muscle part (containing only type IIX and IIB
fibers) and in some cases spanned the entire area of the distal
muscle compartment. 4. FR and FF MUs consisted of muscle
fibers identified histochemically as type IIX and IIB,
respectively. 5. Within each of the FR and FF MU populations,
MUs that were located in the most proximal muscle
compartment were more resistant to fatigue compared with
the units located in the most distal compartment. 6. Cross-
sectional fiber areas were smaller for the proximal FR and FF
fibers, but specific force did not differ among units.
Consequently, when account was taken of the innervation
ratio, the proximal FR and FF units produced less force than
distal units of the same type. Tetanic forces were 87 +/- 27
(SD) mN (proximal FR), 154 +/- 53 (SD) mN (distal FR), 142 +/-
25 (SD) mN (proximal FF), and 229 +/- 86 (SD) mN (distal FF).
7. The present findings suggest that with increasing demand
placed on rat MG during in vivo locomotion, recruitment is
likely to proceed from proximal to distal muscle parts within
the FR and FF MU populations.. 9005-79-2.
93. Dickenson, A. H. Opioid receptors: electrophysiological and
neurophysiological approaches. Acta-Anaesthesiol-Belg. 1996;
47(3): 101-4; ISSN: 0001-5164.
BELGIUM. 0; 0; 0.
94. Dickenson, A. H. Opioid receptors: electrophysiological and
neurophysiological approaches. Acta-Anaesthesiol-Belg. 1996;
47(3): 101-4; ISSN: 0001-5164.
BELGIUM. 0; 0; 0.
95. Dickinson, P. J.; Fanarraga, M. L.; Griffiths, I. R.; Barrie, J. M.;
Kyriakides, E.; Montague, P. Oligodendrocyte progenitors in the
embryonic spinal cord express DM-20. Neuropathol-Appl-
Neurobiol. 1996 Jun; 22(3): 188-98; ISSN: 0305-1846.
ENGLAND. Oligodendrocyte progenitors, originating in the
ventral ventricular zone of the embryonic rodent spinal cord,
migrate and differentiate into the oligodendrocytes
myelinating the future white matter. Transcripts for the dm-
20 isoform of the proteolipid protein (plp) gene are detectable
initially in cells of the ventral ventricular region of the
embryonic central canal and subsequently throughout the white
matter. The dm-20+ cells are present several days before
oligodendrocytes or myelin sheaths are detectable. The
purpose of the present study was to determine if DM-20
protein is present and whether DM-20+ cells can be linked to
the oligodendrocyte lineage in the mouse spinal cord.
Expression of plp and dm-20 transcripts and product was
monitored using reverse transcription polymerase chain
reaction (RT-PCR), and in situ hybridization and
immunostaining of cryosections and associated cultures. Cell
identification was performed using antigenic markers
characterizing different stages of oligodendrocyte
differentiation. We show a temporal and spatial progression of
cells expressing dm-20 transcripts and product from the
ventral ventricular zone at embryonic day 13 (E13.0), via the
lateral borders of the floor plate to the ventral pia and white
matter. The cells, initially devoid of myelin basic protein
(MBP) and PLP, co-express these myelin proteins at
approximately E16.5/17.0. Some DM-20+ cells co-label with
definitive markers of the early oligodendrocyte lineage, are
capable of mitosis and subsequently differentiate into
oligodendrocytes. Other DM-20+ cells may represent earlier
precursor cells. The expression of DM-20 in oligodendrocyte
progenitors is consistent with a postulated role in glial cell
development.. 0; 0; 0; 63231-63-0.
96. Dickinson, P. J.; Fanarraga, M. L.; Griffiths, I. R.; Barrie, J. M.;
Kyriakides, E.; Montague, P. Oligodendrocyte progenitors in the
embryonic spinal cord express DM-20. Neuropathol-Appl-
Neurobiol. 1996 Jun; 22(3): 188-98; ISSN: 0305-1846.
ENGLAND. Oligodendrocyte progenitors, originating in the
ventral ventricular zone of the embryonic rodent spinal cord,
migrate and differentiate into the oligodendrocytes
myelinating the future white matter. Transcripts for the dm-
20 isoform of the proteolipid protein (plp) gene are detectable
initially in cells of the ventral ventricular region of the
embryonic central canal and subsequently throughout the white
matter. The dm-20+ cells are present several days before
oligodendrocytes or myelin sheaths are detectable. The
purpose of the present study was to determine if DM-20
protein is present and whether DM-20+ cells can be linked to
the oligodendrocyte lineage in the mouse spinal cord.
Expression of plp and dm-20 transcripts and product was
monitored using reverse transcription polymerase chain
reaction (RT-PCR), and in situ hybridization and
immunostaining of cryosections and associated cultures. Cell
identification was performed using antigenic markers
characterizing different stages of oligodendrocyte
differentiation. We show a temporal and spatial progression of
cells expressing dm-20 transcripts and product from the
ventral ventricular zone at embryonic day 13 (E13.0), via the
lateral borders of the floor plate to the ventral pia and white
matter. The cells, initially devoid of myelin basic protein
(MBP) and PLP, co-express these myelin proteins at
approximately E16.5/17.0. Some DM-20+ cells co-label with
definitive markers of the early oligodendrocyte lineage, are
capable of mitosis and subsequently differentiate into
oligodendrocytes. Other DM-20+ cells may represent earlier
precursor cells. The expression of DM-20 in oligodendrocyte
progenitors is consistent with a postulated role in glial cell
development.. 0; 0; 0; 63231-63-0.
97. Doige, C. E. Congenital cleft vertebral centrum and intra- and
extraspinal cyst in a foal. Vet-Pathol. 1996 Jan; 33(1): 87-9;
ISSN: 0300-9858.
UNITED-STATES. A midsagittal centrum cleft of T5-6,
malformation and fusion of T3-7, intra- and extraspinal cyst,
and myelodysplasia were found in a 3-month-old female
Arabian foal that had experienced posterior ataxia since birth.
Based on studies in other species, ecto-endodermal adhesions
early in embryogenesis leading to formation of an
enterogenous cyst is the most probable pathogenesis.
98. Doige, C. E. Congenital cleft vertebral centrum and intra- and
extraspinal cyst in a foal. Vet-Pathol. 1996 Jan; 33(1): 87-9;
ISSN: 0300-9858.
UNITED-STATES. A midsagittal centrum cleft of T5-6,
malformation and fusion of T3-7, intra- and extraspinal cyst,
and myelodysplasia were found in a 3-month-old female
Arabian foal that had experienced posterior ataxia since birth.
Based on studies in other species, ecto-endodermal adhesions
early in embryogenesis leading to formation of an
enterogenous cyst is the most probable pathogenesis.
99. Dong, X. W.; Morin, D.; Feldman, J. L. Multiple actions of 1S,3R-
ACPD in modulating endogenous synaptic transmission to
spinal respiratory motoneurons. J-Neurosci. 1996 Aug 15;
16(16): 4971-82; ISSN: 0270-6474.
UNITED-STATES. To determine physiological roles of
metabotropic glutamate receptors (mGluRs) affecting
breathing, we examined the effects of (1S,3R)-1-
aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) on
synaptic transmission and excitability of phrenic motoneurons
(PMNs) in an in vitro neonatal rat brainstem/spinal cord
preparation. The effects of 1S,3R-ACPD were multiple,
including reduction of inspiratory-modulated synaptic
currents and increase of neuronal excitability via an inward
current (Iacpd) associated with a decrease of membrane
conductance. The mechanism underlying synaptic depression
was examined. We found that 1S,3R-ACPD reduced the
frequency but not the amplitude of miniature excitatory
postsynaptic currents. The current induced by exogenous AMPA
was not significantly affected by 1S,3R-ACPD. These results
suggest that 1S,3R-ACPD-induced reduction of inspiratory
synaptic currents is mediated by presynaptic mGluRs. We also
examined the ionic basis for Iacpd. We found that Iacpd had a
reversal potential of approximately -100 mV, close to the
estimated, EK+ (-95 mV). Elevating extracellular [K+] to 9 mM
reduced the Iacpd reversal potential to -75 mV. The K+ channel
blocker Ba2+ induced an inward current with a reversal
potential at -93 mV associated with a decrease of membrane
conductance, closely resembling the effect of 1S,3R-ACPD.
Moreover, Ba2+, occluded 1S,3R-ACPD effects. In the presence
of Ba2+, Iacpd and the 1S,3R-ACPD-induced decrease of
membrane conductance were diminished. Our data indicate that
the dominant component of Iacpd results from the blockade of
a Ba(2+)-sensitive resting K+ conductance. We conclude that
the activation of mGluRs affects the inspiratory-modulated
activity of PMNs via distinct mechanisms at pre- and
postsynaptic sites.. 0; 111900-32-4; 52-52-8.
100. Dong, X. W.; Morin, D.; Feldman, J. L. Multiple actions of 1S,3R-
ACPD in modulating endogenous synaptic transmission to
spinal respiratory motoneurons. J-Neurosci. 1996 Aug 15;
16(16): 4971-82; ISSN: 0270-6474.
UNITED-STATES. To determine physiological roles of
metabotropic glutamate receptors (mGluRs) affecting
breathing, we examined the effects of (1S,3R)-1-
aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) on
synaptic transmission and excitability of phrenic motoneurons
(PMNs) in an in vitro neonatal rat brainstem/spinal cord
preparation. The effects of 1S,3R-ACPD were multiple,
including reduction of inspiratory-modulated synaptic
currents and increase of neuronal excitability via an inward
current (Iacpd) associated with a decrease of membrane
conductance. The mechanism underlying synaptic depression
was examined. We found that 1S,3R-ACPD reduced the
frequency but not the amplitude of miniature excitatory
postsynaptic currents. The current induced by exogenous AMPA
was not significantly affected by 1S,3R-ACPD. These results
suggest that 1S,3R-ACPD-induced reduction of inspiratory
synaptic currents is mediated by presynaptic mGluRs. We also
examined the ionic basis for Iacpd. We found that Iacpd had a
reversal potential of approximately -100 mV, close to the
estimated, EK+ (-95 mV). Elevating extracellular [K+] to 9 mM
reduced the Iacpd reversal potential to -75 mV. The K+ channel
blocker Ba2+ induced an inward current with a reversal
potential at -93 mV associated with a decrease of membrane
conductance, closely resembling the effect of 1S,3R-ACPD.
Moreover, Ba2+, occluded 1S,3R-ACPD effects. In the presence
of Ba2+, Iacpd and the 1S,3R-ACPD-induced decrease of
membrane conductance were diminished. Our data indicate that
the dominant component of Iacpd results from the blockade of
a Ba(2+)-sensitive resting K+ conductance. We conclude that
the activation of mGluRs affects the inspiratory-modulated
activity of PMNs via distinct mechanisms at pre- and
postsynaptic sites.. 0; 111900-32-4; 52-52-8.
101. Dowman, R. Effects of operantly conditioning the amplitude of the
P200 peak of the SEP on pain sensitivity and the spinal
nociceptive withdrawal reflex in humans. Psychophysiology.
1996 May; 33(3): 252-61; ISSN: 0048-5772.
UNITED-STATES. This study attempted to replicate and extend
earlier work that reported that the amplitude of the P200 peak
of the human somatosensory evoked potential (SEP) can be
increased and decreased when reward is made contingent upon
change and that these changes are accompanied by alterations
in pain sensitivity. Twenty-one subjects were able to make
the amplitude of the P200 peak evoked by sural nerve
stimulation larger during increased training (up-training) than
during decreased training (down-training). There were no
differences in the sural nerve compound action potential
between up-training and down-training. This finding
demonstrates that the change in P200 amplitude was not due
to a change in stimulus efficacy, but rather to a change within
the central nervous system. Subjective pain ratings and a
nociceptive spinal reflex were the same in up-training as in
down-training. Thus, conditioned changes in P200 amplitude do
not alter pain sensitivity.
102. Dowman, R. Effects of operantly conditioning the amplitude of the
P200 peak of the SEP on pain sensitivity and the spinal
nociceptive withdrawal reflex in humans. Psychophysiology.
1996 May; 33(3): 252-61; ISSN: 0048-5772.
UNITED-STATES. This study attempted to replicate and extend
earlier work that reported that the amplitude of the P200 peak
of the human somatosensory evoked potential (SEP) can be
increased and decreased when reward is made contingent upon
change and that these changes are accompanied by alterations
in pain sensitivity. Twenty-one subjects were able to make
the amplitude of the P200 peak evoked by sural nerve
stimulation larger during increased training (up-training) than
during decreased training (down-training). There were no
differences in the sural nerve compound action potential
between up-training and down-training. This finding
demonstrates that the change in P200 amplitude was not due
to a change in stimulus efficacy, but rather to a change within
the central nervous system. Subjective pain ratings and a
nociceptive spinal reflex were the same in up-training as in
down-training. Thus, conditioned changes in P200 amplitude do
not alter pain sensitivity.
103. Dumitrescu, R. V.; Michalek Sauberer, A.; Gradwohl Matis, I.;
Wildling, E.; Spiss, C. K.; Illievich, U. M. Nonpharmacological
neuronal protection. Acta-Anaesthesiol-Scand-Suppl. 1996;
109: 59-60; ISSN: 0515-2720.
DENMARK. 0.
104. Dumitrescu, R. V.; Michalek Sauberer, A.; Gradwohl Matis, I.;
Wildling, E.; Spiss, C. K.; Illievich, U. M. Nonpharmacological
neuronal protection. Acta-Anaesthesiol-Scand-Suppl. 1996;
109: 59-60; ISSN: 0515-2720.
DENMARK. 0.
105. Ebens, A.; Brose, K.; Leonardo, E. D.; Hanson, MG Jr; Bladt, F.;
Birchmeier, C.; Barres, B. A.; Tessier Lavigne, M. Hepatocyte
growth factor/scatter factor is an axonal chemoattractant and
a neurotrophic factor for spinal motor neurons. Neuron. 1996
Dec; 17(6): 1157-72; ISSN: 0896-6273.
UNITED-STATES. In the embryonic nervous system, developing
axons can be guided to their targets by diffusible factors
secreted by their intermediate and final cellular targets. To
date only one family of chemoattractants for developing axons
has been identified. Grafting and ablation experiments in fish,
amphibians, and birds have suggested that spinal motor axons
are guided to their targets in the limb in part by a succession
of chemoattractants made by the sclerotome and by the limb
mesenchyme, two intermediate targets that these axons
encounter en route to their target muscles. Here we identify
the limb mesenchyme-derived chemoattractant as hepatocyte
growth factor/scatter factor (HGF/SF), a diffusible ligand for
the c-Met receptor tyrosine kinase, and we also implicate
HGF/SF at later stages as a muscle-derived survival factor for
motoneurons. These results indicate that, in addition to
functioning as a mitogen, a motogen, and a morphogen in
nonneural systems, HGF/SF can function as a guidance and
survival factor in the developing nervous system.. 0; 0;
67256-21-7.
106. Ebens, A.; Brose, K.; Leonardo, E. D.; Hanson, MG Jr; Bladt, F.;
Birchmeier, C.; Barres, B. A.; Tessier Lavigne, M. Hepatocyte
growth factor/scatter factor is an axonal chemoattractant and
a neurotrophic factor for spinal motor neurons. Neuron. 1996
Dec; 17(6): 1157-72; ISSN: 0896-6273.
UNITED-STATES. In the embryonic nervous system, developing
axons can be guided to their targets by diffusible factors
secreted by their intermediate and final cellular targets. To
date only one family of chemoattractants for developing axons
has been identified. Grafting and ablation experiments in fish,
amphibians, and birds have suggested that spinal motor axons
are guided to their targets in the limb in part by a succession
of chemoattractants made by the sclerotome and by the limb
mesenchyme, two intermediate targets that these axons
encounter en route to their target muscles. Here we identify
the limb mesenchyme-derived chemoattractant as hepatocyte
growth factor/scatter factor (HGF/SF), a diffusible ligand for
the c-Met receptor tyrosine kinase, and we also implicate
HGF/SF at later stages as a muscle-derived survival factor for
motoneurons. These results indicate that, in addition to
functioning as a mitogen, a motogen, and a morphogen in
nonneural systems, HGF/SF can function as a guidance and
survival factor in the developing nervous system.. 0; 0;
67256-21-7.
107. Eide, A. L.; Glover, J. C. Development of an identified spinal
commissural interneuron population in an amniote: neurons of
the avian Hofmann nuclei. J-Neurosci. 1996 Sep 15; 16(18):
5749-61; ISSN: 0270-6474.
UNITED-STATES. The commissural interneurons of the
Hofmann nuclei (HN) of the avian spinal cord (The axonal
projections of the Hofmann nuclei in the spinal cord of the late
stage chicken embryo, Anat Embryol (Berl), A.L. Eide, 1996, Vol
193, pp 543-557) provide a unique opportunity to describe the
development of an identified spinal commissural axon
projection and its terminal collaterals in an amniote
vertebrate. Here, we use the lipophilic tracer Dil to label these
and other commissural projections anterogradely and
retrogradely from the time the HN neurons are born.
[3H]thymidine birthdating shows that the final mitoses of HN
neurons occur at stages 21-24 [developmental day (d) 4]. By
direct comparison, this follows the generation of motoneurons
and of large, dorsally located commissural interneurons. The
first HN neurons reach the ventrolateral margin of the spinal
cord by d6 by a radial migration through the ventral horn.
Radial migration occurs after the extension of HN axons across
the midline. Thus, HN neurons are determined to be
commissural interneurons before attaining their definitive
locations. The HN neurons subsequently aggregate into
segmentally iterated clusters at the ventrolateral margin of
the spinal cord by d8. Also by d8 their logitudinal axons attain
mature extent in the ventral funiculus of the contralateral
side and begin to sprout collaterals. The collaterals are
directed predominantly toward the medial aspect of the
ventral horn at all stages, forming by d12 a dense thicket of
terminals that thins out over several segments to each side of
the HN of origin. The initial direction of collateral outgrowth
is largely appropriate for the mature termination pattern of
the HN. Terminal arbors, however, are less focused at early
developmental stages than at later stages.
108. Eide, A. L.; Glover, J. C. Development of an identified spinal
commissural interneuron population in an amniote: neurons of
the avian Hofmann nuclei. J-Neurosci. 1996 Sep 15; 16(18):
5749-61; ISSN: 0270-6474.
UNITED-STATES. The commissural interneurons of the
Hofmann nuclei (HN) of the avian spinal cord (The axonal
projections of the Hofmann nuclei in the spinal cord of the late
stage chicken embryo, Anat Embryol (Berl), A.L. Eide, 1996, Vol
193, pp 543-557) provide a unique opportunity to describe the
development of an identified spinal commissural axon
projection and its terminal collaterals in an amniote
vertebrate. Here, we use the lipophilic tracer Dil to label these
and other commissural projections anterogradely and
retrogradely from the time the HN neurons are born.
[3H]thymidine birthdating shows that the final mitoses of HN
neurons occur at stages 21-24 [developmental day (d) 4]. By
direct comparison, this follows the generation of motoneurons
and of large, dorsally located commissural interneurons. The
first HN neurons reach the ventrolateral margin of the spinal
cord by d6 by a radial migration through the ventral horn.
Radial migration occurs after the extension of HN axons across
the midline. Thus, HN neurons are determined to be
commissural interneurons before attaining their definitive
locations. The HN neurons subsequently aggregate into
segmentally iterated clusters at the ventrolateral margin of
the spinal cord by d8. Also by d8 their logitudinal axons attain
mature extent in the ventral funiculus of the contralateral
side and begin to sprout collaterals. The collaterals are
directed predominantly toward the medial aspect of the
ventral horn at all stages, forming by d12 a dense thicket of
terminals that thins out over several segments to each side of
the HN of origin. The initial direction of collateral outgrowth
is largely appropriate for the mature termination pattern of
the HN. Terminal arbors, however, are less focused at early
developmental stages than at later stages.
109. Ericson, A. C.; Blomqvist, A.; Krout, K.; Craig, A. D. Fine structural
organization of spinothalamic and trigeminothalamic lamina I
terminations in the nucleus submedius of the cat. J-Comp-
Neurol. 1996 Aug 5; 371(4): 497-512; ISSN: 0021-9967.
UNITED-STATES. We examined lamina I trigemino- and
spinothalamic tract (TSTT) terminals labeled with Phaseolus
vulgaris leucoagglutinin in the nucleus submedius (Sm), a
nociceptive relay in the cat's thalamus. Volume-rendered
(three-dimensional) reconstructions of ten lamina I TSTT
terminals identified with light and electron microscopy were
built from serial ultrathin sections by computer, which
enabled the overall structures of the terminal complexes to be
characterized in detail. Two fundamentally different
terminations were observed: compact clusters of numerous
boutons, which predominate in the dense focus of a lamina I
terminal field in the Sm, and boutons-of-passage, which are
present throughout the terminal field and predominate in its
periphery. Reconstructions of cluster terminations reveal that
all boutons of each cluster make synaptic contact with
protrusions and branch points on a single dendrite and involve
presynaptic dendrites (PSDs) in triadic arrangements,
providing a basis for the secure relay of sensory information.
In contrast, reconstructions show that boutons-of-passage are
generally characterized by simple contacts with PSDs,
indicating an ascending inhibitory lamina I influence. These
different synaptic arrangements are consistent with
physiological evidence indicating that the morphologically
distinct nociceptive-specific and thermoreceptive-(cold)-
specific lamina I TSTT neurons terminate differently within
the Sm. Thus, a suitable structural substrate exists in the
cat's Sm for the inhibitory effect of cold on nociception, a
behavioral and physiological phenomenon of fundamental
significance. We conclude that the Sm is more than a simple
relay for nociception, and that it may be an integrative
comparator of ascending modality-selective information that
arrives from neurons in lamina I.. 0; 0.
110. Ericson, A. C.; Blomqvist, A.; Krout, K.; Craig, A. D. Fine structural
organization of spinothalamic and trigeminothalamic lamina I
terminations in the nucleus submedius of the cat. J-Comp-
Neurol. 1996 Aug 5; 371(4): 497-512; ISSN: 0021-9967.
UNITED-STATES. We examined lamina I trigemino- and
spinothalamic tract (TSTT) terminals labeled with Phaseolus
vulgaris leucoagglutinin in the nucleus submedius (Sm), a
nociceptive relay in the cat's thalamus. Volume-rendered
(three-dimensional) reconstructions of ten lamina I TSTT
terminals identified with light and electron microscopy were
built from serial ultrathin sections by computer, which
enabled the overall structures of the terminal complexes to be
characterized in detail. Two fundamentally different
terminations were observed: compact clusters of numerous
boutons, which predominate in the dense focus of a lamina I
terminal field in the Sm, and boutons-of-passage, which are
present throughout the terminal field and predominate in its
periphery. Reconstructions of cluster terminations reveal that
all boutons of each cluster make synaptic contact with
protrusions and branch points on a single dendrite and involve
presynaptic dendrites (PSDs) in triadic arrangements,
providing a basis for the secure relay of sensory information.
In contrast, reconstructions show that boutons-of-passage are
generally characterized by simple contacts with PSDs,
indicating an ascending inhibitory lamina I influence. These
different synaptic arrangements are consistent with
physiological evidence indicating that the morphologically
distinct nociceptive-specific and thermoreceptive-(cold)-
specific lamina I TSTT neurons terminate differently within
the Sm. Thus, a suitable structural substrate exists in the
cat's Sm for the inhibitory effect of cold on nociception, a
behavioral and physiological phenomenon of fundamental
significance. We conclude that the Sm is more than a simple
relay for nociception, and that it may be an integrative
comparator of ascending modality-selective information that
arrives from neurons in lamina I.. 0; 0.
111. Ersahin, Y.; Demirtas, E.; Mutluer, S.; Tosun, A. R.; Saydam, S. Split
cord malformations: report of three unusual cases. Pediatr-
Neurosurg. 1996; 24(3): 155-9; ISSN: 1016-2291.
SWITZERLAND. The unified theory, proposed by Pang et al.,
explains the embryogenetic mechanisms of all variants of
split cord malformations (SCMs). All SCMs originate from one
basic error occurring around the time when the primitive
neurenteric canal closes. The basic error is the formation of
an accessory neurenteric canal between the yolk sac and
amnion which is subsequently invested with mesenchyme to
form an endomesenchymal tract that splits the notochord and
neural plate. Three cases of SCMs which support this unified
theory are presented. A 3-month-old girl had a combination of
both types of SCMs at the level of T11. The 2nd case, a 2-
week-old girl, had type-II SCM associated with a thickened
filum terminale, lipomyelomeningocele and ectopic renal
tissue within lipoma. A lipomatous tract extending from a
subcutaneous lipoma to the intradural fibrous septum
contained lymphoid tissues and tubular epithelia in a 3-month-
old boy with a type-II SCM. These 3 cases support the unified
theory.
112. Ersahin, Y.; Demirtas, E.; Mutluer, S.; Tosun, A. R.; Saydam, S. Split
cord malformations: report of three unusual cases. Pediatr-
Neurosurg. 1996; 24(3): 155-9; ISSN: 1016-2291.
SWITZERLAND. The unified theory, proposed by Pang et al.,
explains the embryogenetic mechanisms of all variants of
split cord malformations (SCMs). All SCMs originate from one
basic error occurring around the time when the primitive
neurenteric canal closes. The basic error is the formation of
an accessory neurenteric canal between the yolk sac and
amnion which is subsequently invested with mesenchyme to
form an endomesenchymal tract that splits the notochord and
neural plate. Three cases of SCMs which support this unified
theory are presented. A 3-month-old girl had a combination of
both types of SCMs at the level of T11. The 2nd case, a 2-
week-old girl, had type-II SCM associated with a thickened
filum terminale, lipomyelomeningocele and ectopic renal
tissue within lipoma. A lipomatous tract extending from a
subcutaneous lipoma to the intradural fibrous septum
contained lymphoid tissues and tubular epithelia in a 3-month-
old boy with a type-II SCM. These 3 cases support the unified
theory.
113. Ertekin, C.; Mungan, B.; Uludag, B. Sacral cord conduction time of
the soleus H-reflex. J-Clin-Neurophysiol. 1996 Jan; 13(1): 77-
83; ISSN: 0736-0258.
UNITED-STATES. The sacral cord conduction time of the soleus
H-reflex was investigated in 30 normal adult subjects using
three different methods. (1) The posterior tibial nerve was
stimulated at the popliteal fossa by graded electric shocks,
and the recordings were made from different lumbar epidural
intervertebral levels. The afferent action potentials from the
dorsal roots and the reflexively evoked efferent action
potentials from the ventral roots were recorded. The time
interval between the negative peaks of the ventral and dorsal
root potentials was used to calculate the approximate sacral
cord reflex delay time, which was found to be 1.3 ms. on
average. (2) The sacral cord reflex delay time was found to be
about 2.0 ms using the conduction time of the afferent, that of
the efferent limbs and total reflex time of the soleus H-
response. (3) By stimulating the lumbosacral roots at the
epidural levels and using the difference between the soleus H
and M response latencies, the sacral cord reflex delay was
determined to be approximately 2.4 ms. These findings
indicated that the soleus H-reflex is exclusively
monosynaptic. It is proposed that in humans the synaptic
transmission at the sacral cord is approximately 0.4 ms.
114. Ertekin, C.; Mungan, B.; Uludag, B. Sacral cord conduction time of
the soleus H-reflex. J-Clin-Neurophysiol. 1996 Jan; 13(1): 77-
83; ISSN: 0736-0258.
UNITED-STATES. The sacral cord conduction time of the soleus
H-reflex was investigated in 30 normal adult subjects using
three different methods. (1) The posterior tibial nerve was
stimulated at the popliteal fossa by graded electric shocks,
and the recordings were made from different lumbar epidural
intervertebral levels. The afferent action potentials from the
dorsal roots and the reflexively evoked efferent action
potentials from the ventral roots were recorded. The time
interval between the negative peaks of the ventral and dorsal
root potentials was used to calculate the approximate sacral
cord reflex delay time, which was found to be 1.3 ms. on
average. (2) The sacral cord reflex delay time was found to be
about 2.0 ms using the conduction time of the afferent, that of
the efferent limbs and total reflex time of the soleus H-
response. (3) By stimulating the lumbosacral roots at the
epidural levels and using the difference between the soleus H
and M response latencies, the sacral cord reflex delay was
determined to be approximately 2.4 ms. These findings
indicated that the soleus H-reflex is exclusively
monosynaptic. It is proposed that in humans the synaptic
transmission at the sacral cord is approximately 0.4 ms.
115. Fang, F.; Proudfit, H. K. Spinal cholinergic and monoamine
receptors mediate the antinociceptive effect of morphine
microinjected in the periaqueductal gray on the rat tail, but
not the feet. Brain-Res. 1996 May 25; 722(1-2): 95-108; ISSN:
0006-8993.
NETHERLANDS. The antinociceptive effects of morphine (5
micrograms) microinjected into the ventrolateral
periaqueductal gray were determined using both the tail flick
and the foot withdrawal responses to noxious radiant heating
in lightly anesthetized rats. Intrathecal injection of
appropriate antagonists was used to determine whether the
antinociceptive effects of morphine were mediated by alpha 2-
noradrenergic, serotonergic, opioid, or cholinergic muscarinic
receptors. The increase in the foot withdrawal response
latency produced by microinjection of morphine in the
ventrolateral periaqueductal gray was reversed by intrathecal
injection of the cholinergic muscarinic receptor antagonist
atropine, but was not affected by the alpha 2-adrenoceptor
antagonist yohimbine, the serotonergic receptor antagonist
methysergide, or the opioid receptor antagonist naloxone. In
contrast, the increase in the tail flick response latency
produced by morphine was reduced by either yohimbine,
methysergide or atropine. These results indicate that
microinjection of morphine in the ventrolateral periaqueductal
gray inhibits nociceptive responses to noxious heating of the
tail by activating descending neuronal systems that are
different from those that inhibits the nociceptive responses to
noxious heating of the feet. More specifically, serotonergic,
muscarinic cholinergic and alpha 2-noradrenergic receptors
appear to mediate the antinociception produced by morphine
using the tail flick test. In contrast, muscarinic cholinergic,
but not monoamine receptors appear to mediate the
antinociceptive effects of morphine using the foot withdrawal
response.. 0; 0; 0; 146-48-5; 361-37-5; 465-65-6; 51-55-8;
57-27-2.
116. Fang, F.; Proudfit, H. K. Spinal cholinergic and monoamine
receptors mediate the antinociceptive effect of morphine
microinjected in the periaqueductal gray on the rat tail, but
not the feet. Brain-Res. 1996 May 25; 722(1-2): 95-108; ISSN:
0006-8993.
NETHERLANDS. The antinociceptive effects of morphine (5
micrograms) microinjected into the ventrolateral
periaqueductal gray were determined using both the tail flick
and the foot withdrawal responses to noxious radiant heating
in lightly anesthetized rats. Intrathecal injection of
appropriate antagonists was used to determine whether the
antinociceptive effects of morphine were mediated by alpha 2-
noradrenergic, serotonergic, opioid, or cholinergic muscarinic
receptors. The increase in the foot withdrawal response
latency produced by microinjection of morphine in the
ventrolateral periaqueductal gray was reversed by intrathecal
injection of the cholinergic muscarinic receptor antagonist
atropine, but was not affected by the alpha 2-adrenoceptor
antagonist yohimbine, the serotonergic receptor antagonist
methysergide, or the opioid receptor antagonist naloxone. In
contrast, the increase in the tail flick response latency
produced by morphine was reduced by either yohimbine,
methysergide or atropine. These results indicate that
microinjection of morphine in the ventrolateral periaqueductal
gray inhibits nociceptive responses to noxious heating of the
tail by activating descending neuronal systems that are
different from those that inhibits the nociceptive responses to
noxious heating of the feet. More specifically, serotonergic,
muscarinic cholinergic and alpha 2-noradrenergic receptors
appear to mediate the antinociception produced by morphine
using the tail flick test. In contrast, muscarinic cholinergic,
but not monoamine receptors appear to mediate the
antinociceptive effects of morphine using the foot withdrawal
response.. 0; 0; 0; 146-48-5; 361-37-5; 465-65-6; 51-55-8;
57-27-2.
117. Fetz, E. E.; Perlmutter, S. I.; Maier, M. A.; Flament, D.; Fortier, P. A.
Response patterns and postspike effects of premotor neurons
in cervical spinal cord of behaving monkeys. Can-J-Physiol-
Pharmacol. 1996 Apr; 74(4): 531-46; ISSN: 0008-4212.
CANADA. Most of our information about spinal neurons has
been derived from experiments with anesthetized or
surgically. reduced preparations. To investigate these neurons
under normal behavioral conditions, we recorded the activity
of single afferent units in cervical dorsal root ganglia and of
single interneurons in the cervical spinal cord of macaque
monkeys, as they generated alternating flexion and extension
torques about the wrist. Spike-triggered averages of rectified
electromyographic activity were used to identify "premotor"
(PreM) units associated with correlated postspike effects in
active muscles. In addition to postspike effects, some spike-
triggered averages showed early increases in average muscle
activity, which were attributed to synchronous discharges in
other PreM units. In recordings of peripheral afferents, 49% of
the task-related dorsal root ganglia units produced postspike
facilitation (PSF) of at least one forearm muscle, with a mean
PSF latency of 5.8 +/- 0.3 ms (SE). The PSF amplitude was
measured as the mean percent increase (MPI): the average
increase of the PSF as a percentage of the prespike baseline
mean. PreM afferent units produced PSF with an average MPI of
4.6 +/- 0.3%. In a study of cervical interneurons, about 13%
(72/562) of the task-related cells showed postspike effects.
These PreM interneurons had a mean PSF latency of 7.2 +/- 0.3
ms and a mean MPI of 4.6 +/- 0.2%. The MPI values for spinal
neurons were similar to the MPIs reported for
rubromotoneuronal and corticomotoneuronal cells. PreM
neurons usually facilitated a subset of the coactivated
muscles called the unit's "muscle field." The PreM afferents
facilitated an average of 46% of the synergistically
coactivated muscles, while PreM interneurons facilitated an
average of 37%. These are comparable with the percentage of
muscles facilitated by corticomotoneuronal (40%) and
rubromotoneuronal (50%) cells. During the step-tracking task
the monkeys generated ramp-and-hold torques about the wrist.
The PreM afferents typically became active during either
flexion or extension of the wrist, although a few were
bidirectionally active. The most common response pattern in
PreM afferents was a tonic discharge, followed by phasic and
phasic-tonic discharge. The most common patterns exhibited
by PreM interneurons were tonic and phasic-tonic responses.
PreM afferent units began to discharge on average 51 +/- 13
ms before activation of their target muscle. This early onset
supports our hypothesis that these PreM afferents arose from
muscle spindles, which is also consistent with their short-
latency PSF and their responses to perturbations that
stretched their target muscles. The results reveal some
salient differences between the discharge properties of dorsal
root ganglia neurons, spinal interneurons, and supraspinal PreM
cells in the motor cortex and red nucleus. All four PreM
populations include tonic, phasic-tonic, and phasic cells, but
in significantly different proportions. Most PreM afferents
resembled corticomotoneuronal cells in being active only with
their target muscles, unlike rubromotoneuronal cells and
spinal PreM interneurons, which tended to exhibit more
bidirectional discharges.
118. Fetz, E. E.; Perlmutter, S. I.; Maier, M. A.; Flament, D.; Fortier, P. A.
Response patterns and postspike effects of premotor neurons
in cervical spinal cord of behaving monkeys. Can-J-Physiol-
Pharmacol. 1996 Apr; 74(4): 531-46; ISSN: 0008-4212.
CANADA. Most of our information about spinal neurons has
been derived from experiments with anesthetized or
surgically. reduced preparations. To investigate these neurons
under normal behavioral conditions, we recorded the activity
of single afferent units in cervical dorsal root ganglia and of
single interneurons in the cervical spinal cord of macaque
monkeys, as they generated alternating flexion and extension
torques about the wrist. Spike-triggered averages of rectified
electromyographic activity were used to identify "premotor"
(PreM) units associated with correlated postspike effects in
active muscles. In addition to postspike effects, some spike-
triggered averages showed early increases in average muscle
activity, which were attributed to synchronous discharges in
other PreM units. In recordings of peripheral afferents, 49% of
the task-related dorsal root ganglia units produced postspike
facilitation (PSF) of at least one forearm muscle, with a mean
PSF latency of 5.8 +/- 0.3 ms (SE). The PSF amplitude was
measured as the mean percent increase (MPI): the average
increase of the PSF as a percentage of the prespike baseline
mean. PreM afferent units produced PSF with an average MPI of
4.6 +/- 0.3%. In a study of cervical interneurons, about 13%
(72/562) of the task-related cells showed postspike effects.
These PreM interneurons had a mean PSF latency of 7.2 +/- 0.3
ms and a mean MPI of 4.6 +/- 0.2%. The MPI values for spinal
neurons were similar to the MPIs reported for
rubromotoneuronal and corticomotoneuronal cells. PreM
neurons usually facilitated a subset of the coactivated
muscles called the unit's "muscle field." The PreM afferents
facilitated an average of 46% of the synergistically
coactivated muscles, while PreM interneurons facilitated an
average of 37%. These are comparable with the percentage of
muscles facilitated by corticomotoneuronal (40%) and
rubromotoneuronal (50%) cells. During the step-tracking task
the monkeys generated ramp-and-hold torques about the wrist.
The PreM afferents typically became active during either
flexion or extension of the wrist, although a few were
bidirectionally active. The most common response pattern in
PreM afferents was a tonic discharge, followed by phasic and
phasic-tonic discharge. The most common patterns exhibited
by PreM interneurons were tonic and phasic-tonic responses.
PreM afferent units began to discharge on average 51 +/- 13
ms before activation of their target muscle. This early onset
supports our hypothesis that these PreM afferents arose from
muscle spindles, which is also consistent with their short-
latency PSF and their responses to perturbations that
stretched their target muscles. The results reveal some
salient differences between the discharge properties of dorsal
root ganglia neurons, spinal interneurons, and supraspinal PreM
cells in the motor cortex and red nucleus. All four PreM
populations include tonic, phasic-tonic, and phasic cells, but
in significantly different proportions. Most PreM afferents
resembled corticomotoneuronal cells in being active only with
their target muscles, unlike rubromotoneuronal cells and
spinal PreM interneurons, which tended to exhibit more
bidirectional discharges.
119. Fields, H. L.; Malick, A.; Burstein, R. Dorsal horn projection targets
of ON and OFF cells in the rostral ventromedial medulla. J-
Neurophysiol. 1995 Oct; 74(4): 1742-59; ISSN: 0022-3077.
UNITED-STATES. 1. The rostral ventromedial medulla (RVM)
participates in the modulation of nociceptive transmission by
spinal cord neurons. Previous anatomic studies have
demonstrated that RVM neurons project to laminae I, II, and V
of the dorsal horn; laminae VII and VIII of the intermediate and
ventral horns; the intermediolateral column; and lamina X. The
RVM contains at least three physiologically defined classes of
neurons, two of which, the ON and the OFF cells, have been
implicated in nociceptive modulation. Because these cells
classes are intermingled in the RVM, it has not been possible
to determine the spinal laminar projection targets of ON and
OFF cells by anatomic methods. Therefore in the current study
we employed antidromic microstimulation methods to
determine the laminar projections of two of the three classes
of RVM neurons, the ON and the OFF cells. 2. In lightly
anesthetized (with methohexital sodium) rats, single-unit
extracellular recordings were made from 48 RVM neurons that
were physiologically characterized as ON (30) or OFF (18)
cells. The recording locations of 45 of these neurons were
recovered. Thirty-seven were found in the nucleus raphe
magnus and eight were located near its dorsal and lateral
borders. 3. Thirty-two physiologically identified RVM neurons
(18 ON and 14 OFF cells) were antidromically activated from
the cervical spinal cord using a monopolar stimulating
electrode. The stimulating electrode was moved
systematically in the white matter until antidromic activation
could be produced with currents of < or = 20 microA (6.1 +/-
0.7 microA, mean +/- SE). The points from which minimum
currents were required to antidromically activate the neurons
were located mainly in the ipsilateral dorsolateral funiculus
(DLF) (27 of 32). In a few cases, lowest antidromic threshold
currents were found near the border between the DLF and
ventrolateral funiculus (VLF) or, rarely, in the VLF itself. In
these cases, the cell recordings were found to be near the
dorsal boundary of the RVM. 4. While one electrode was used to
stimulate the parent axon in the lateral funiculus, a second
was used to explore the gray matter for the presence of
collateral branches. The identification of a branch was
initially determined by an increase in antidromic latency. At
the same rostrocaudal plane of the spinal cord, stimulation of
the DLF induced an antidromic spike that invaded the neuron
earlier than the antidromic spike elicited by stimulation in the
gray matter. Collateral branches were confirmed by
establishing that the location of the minimum threshold point
for antidromic activation of the neurons from the second
electrode was in the gray matter, that the minimum current
required to antidromically activate the neuron from that point
was too low to activate the parent axon in the DLF, and that a
collision occurred between the spikes induced by the two
stimulating electrodes. 5. In 17 cases, physiologically
identified RVM neurons (10 ON and 7 OFF cells) were
antidromically activated from the gray matter of the cervical
spinal cord using a current of 8.4 +/- 2.1 (SE) microA. Minimum
threshold points for antidromic activation were found in
laminae I-II (3 ON and 4 OFF cells), lamina V (5 ON and 6 OFF
cells), and regions ventral to the lateral reticulated area (3 ON
and 2 OFF cells) of the gray matter. As indicated by these
numbers, some neurons were antidromically activated from
more than one gray matter region. In general, all OFF cells and
9 of 10 ON cells were antidromically activated from low
threshold points in either laminae I-II or lamina V. 6. In six
cases, neurons were activated from separate points located in
two or three different laminae of the gray matter. Three OFF
cells were activated from laminae I-II and V, one OFF cell and
one ON cell were activated from lamina V and from more
ventral points, and one ON cell was activated from laminae I-II
and from points ventral to lamina V.
120. Fields, H. L.; Malick, A.; Burstein, R. Dorsal horn projection targets
of ON and OFF cells in the rostral ventromedial medulla. J-
Neurophysiol. 1995 Oct; 74(4): 1742-59; ISSN: 0022-3077.
UNITED-STATES. 1. The rostral ventromedial medulla (RVM)
participates in the modulation of nociceptive transmission by
spinal cord neurons. Previous anatomic studies have
demonstrated that RVM neurons project to laminae I, II, and V
of the dorsal horn; laminae VII and VIII of the intermediate and
ventral horns; the intermediolateral column; and lamina X. The
RVM contains at least three physiologically defined classes of
neurons, two of which, the ON and the OFF cells, have been
implicated in nociceptive modulation. Because these cells
classes are intermingled in the RVM, it has not been possible
to determine the spinal laminar projection targets of ON and
OFF cells by anatomic methods. Therefore in the current study
we employed antidromic microstimulation methods to
determine the laminar projections of two of the three classes
of RVM neurons, the ON and the OFF cells. 2. In lightly
anesthetized (with methohexital sodium) rats, single-unit
extracellular recordings were made from 48 RVM neurons that
were physiologically characterized as ON (30) or OFF (18)
cells. The recording locations of 45 of these neurons were
recovered. Thirty-seven were found in the nucleus raphe
magnus and eight were located near its dorsal and lateral
borders. 3. Thirty-two physiologically identified RVM neurons
(18 ON and 14 OFF cells) were antidromically activated from
the cervical spinal cord using a monopolar stimulating
electrode. The stimulating electrode was moved
systematically in the white matter until antidromic activation
could be produced with currents of < or = 20 microA (6.1 +/-
0.7 microA, mean +/- SE). The points from which minimum
currents were required to antidromically activate the neurons
were located mainly in the ipsilateral dorsolateral funiculus
(DLF) (27 of 32). In a few cases, lowest antidromic threshold
currents were found near the border between the DLF and
ventrolateral funiculus (VLF) or, rarely, in the VLF itself. In
these cases, the cell recordings were found to be near the
dorsal boundary of the RVM. 4. While one electrode was used to
stimulate the parent axon in the lateral funiculus, a second
was used to explore the gray matter for the presence of
collateral branches. The identification of a branch was
initially determined by an increase in antidromic latency. At
the same rostrocaudal plane of the spinal cord, stimulation of
the DLF induced an antidromic spike that invaded the neuron
earlier than the antidromic spike elicited by stimulation in the
gray matter. Collateral branches were confirmed by
establishing that the location of the minimum threshold point
for antidromic activation of the neurons from the second
electrode was in the gray matter, that the minimum current
required to antidromically activate the neuron from that point
was too low to activate the parent axon in the DLF, and that a
collision occurred between the spikes induced by the two
stimulating electrodes. 5. In 17 cases, physiologically
identified RVM neurons (10 ON and 7 OFF cells) were
antidromically activated from the gray matter of the cervical
spinal cord using a current of 8.4 +/- 2.1 (SE) microA. Minimum
threshold points for antidromic activation were found in
laminae I-II (3 ON and 4 OFF cells), lamina V (5 ON and 6 OFF
cells), and regions ventral to the lateral reticulated area (3 ON
and 2 OFF cells) of the gray matter. As indicated by these
numbers, some neurons were antidromically activated from
more than one gray matter region. In general, all OFF cells and
9 of 10 ON cells were antidromically activated from low
threshold points in either laminae I-II or lamina V. 6. In six
cases, neurons were activated from separate points located in
two or three different laminae of the gray matter. Three OFF
cells were activated from laminae I-II and V, one OFF cell and
one ON cell were activated from lamina V and from more
ventral points, and one ON cell was activated from laminae I-II
and from points ventral to lamina V.
121. Filippini, J. F.; Vincey, P.; Renard, J. C.; Barnabe, D.; Gal, M.;
Grollier, R. [Some useful basics of functional anatomy for a
better understanding of the pain phenomenon]. Quelques
rappels d'anatomie fonctionnelle utiles a la comprehension du
phenomene douloureux. Rev-Laryngol-Otol-Rhinol-Bord. 1996;
117(2): 75-8; ISSN: 0035-1334.
FRANCE. Cannot simply be considered as a nociception
phenomenon: it is more complex than a simple transmission
system that conveys this information to the cerebral cortex. It
is mainly a psychological event. Numerous regulating and
inhibiting effects on incoming pain signals exist, for the most
part located in spinal and thalamic areas; only half of these
are morphine-dependent. Knowledge of these allows a better
approach to chronic pain, using not only medication but also
other techniques such as physiotherapy and music therapy
analgesia.
122. Filippini, J. F.; Vincey, P.; Renard, J. C.; Barnabe, D.; Gal, M.;
Grollier, R. [Some useful basics of functional anatomy for a
better understanding of the pain phenomenon]. Quelques
rappels d'anatomie fonctionnelle utiles a la comprehension du
phenomene douloureux. Rev-Laryngol-Otol-Rhinol-Bord. 1996;
117(2): 75-8; ISSN: 0035-1334.
FRANCE. Cannot simply be considered as a nociception
phenomenon: it is more complex than a simple transmission
system that conveys this information to the cerebral cortex. It
is mainly a psychological event. Numerous regulating and
inhibiting effects on incoming pain signals exist, for the most
part located in spinal and thalamic areas; only half of these
are morphine-dependent. Knowledge of these allows a better
approach to chronic pain, using not only medication but also
other techniques such as physiotherapy and music therapy
analgesia.
123. Forger, N. G.; Galef, BG Jr; Clark, M. M. Intrauterine position
affects motoneuron number and muscle size in a sexually
dimorphic neuromuscular system. Brain-Res. 1996 Sep 30;
735(1): 119-24; ISSN: 0006-8993.
NETHERLANDS. The intrauterine position occupied by a rodent
fetus influences the amount of testosterone to which it is
exposed before birth. Animals that are gestated between two
male fetuses (2M) are exposed to higher circulating levels of
testosterone than are animals positioned between two female
fetuses (2F) and there are reliable differences in the
reproductive physiology and behavior of 2M and 2F animals
when adult. To determine whether intrauterine position
modifies development of the central nervous system, we
examined the sexually dimorphic spinal nucleus of the
bulbocavernosus (SNB) in male and female gerbils from known
intrauterine positions. We found that adult 2M female gerbils
had 16% more SNB motoneurons than did 2F females. 2M males
did not differ from 2F males in SNB motoneuron number, but
the bulbocavernosus muscle, which is innervated by SNB
motoneurons, was approximately 50% larger in 2M than in 2F
males. These data indicate that intrauterine position can
influence the morphology of the sexually dimorphic SNB
neuromuscular system.
124. Forger, N. G.; Galef, BG Jr; Clark, M. M. Intrauterine position
affects motoneuron number and muscle size in a sexually
dimorphic neuromuscular system. Brain-Res. 1996 Sep 30;
735(1): 119-24; ISSN: 0006-8993.
NETHERLANDS. The intrauterine position occupied by a rodent
fetus influences the amount of testosterone to which it is
exposed before birth. Animals that are gestated between two
male fetuses (2M) are exposed to higher circulating levels of
testosterone than are animals positioned between two female
fetuses (2F) and there are reliable differences in the
reproductive physiology and behavior of 2M and 2F animals
when adult. To determine whether intrauterine position
modifies development of the central nervous system, we
examined the sexually dimorphic spinal nucleus of the
bulbocavernosus (SNB) in male and female gerbils from known
intrauterine positions. We found that adult 2M female gerbils
had 16% more SNB motoneurons than did 2F females. 2M males
did not differ from 2F males in SNB motoneuron number, but
the bulbocavernosus muscle, which is innervated by SNB
motoneurons, was approximately 50% larger in 2M than in 2F
males. These data indicate that intrauterine position can
influence the morphology of the sexually dimorphic SNB
neuromuscular system.
125. Fraher, J. Node distribution and packing density in the rat CNS-
PNS transitional zone. Microsc-Res-Tech. 1996 Aug 15; 34(6):
507-21; ISSN: 1059-910X.
UNITED-STATES. The density of nodes of Ranvier was
examined at CNS, PNS, and transitional zone (TZ) levels of rat
lumbar ventral motoneurone fibres. It was found to be
significantly greater in the TZ than at the other levels: The
difference was sevenfold for the ventral root and at least
fourfold for central fibre levels. Node distribution and spacing
was examined within the two main types of TZ found in rat
ventral rootlets: the first, in which the TZ is short and is
approximately on a level with the surface of the cord; and the
second, in which it is much longer and extends into the
proximal part of the rootlet. Node spacing was estimated as
nearest neighbour distance, the true distance between
adjacent node centres. This is a better estimate of node
spacing than simple density since it measures the actual
linear distance between nodes over which any interaction
between them would be likely to take place. Despite marked
differences in the dimensions of the two types of TZ, nearest
neighbour distance distribution was very similar in each,
suggesting that similar mechanisms may influence their
spacing during development. The TZ contains especially large
amounts of interstitial tissue, mainly composed of astrocyte
processes, separating the fibres traversing it. The proportion
of the TZ composed of interstitium was over three times that
in the ventral root and nearly twice that at the CNS level
studied. The large amounts of astrocytic tissue in the TZ may
be related to the high packing density of nodes. It may function
to regulate extracellular ionic concentrations in the TZ and to
maintain a stable ionic environment for the transitional nodes.
126. Fraher, J. Node distribution and packing density in the rat CNS-
PNS transitional zone. Microsc-Res-Tech. 1996 Aug 15; 34(6):
507-21; ISSN: 1059-910X.
UNITED-STATES. The density of nodes of Ranvier was
examined at CNS, PNS, and transitional zone (TZ) levels of rat
lumbar ventral motoneurone fibres. It was found to be
significantly greater in the TZ than at the other levels: The
difference was sevenfold for the ventral root and at least
fourfold for central fibre levels. Node distribution and spacing
was examined within the two main types of TZ found in rat
ventral rootlets: the first, in which the TZ is short and is
approximately on a level with the surface of the cord; and the
second, in which it is much longer and extends into the
proximal part of the rootlet. Node spacing was estimated as
nearest neighbour distance, the true distance between
adjacent node centres. This is a better estimate of node
spacing than simple density since it measures the actual
linear distance between nodes over which any interaction
between them would be likely to take place. Despite marked
differences in the dimensions of the two types of TZ, nearest
neighbour distance distribution was very similar in each,
suggesting that similar mechanisms may influence their
spacing during development. The TZ contains especially large
amounts of interstitial tissue, mainly composed of astrocyte
processes, separating the fibres traversing it. The proportion
of the TZ composed of interstitium was over three times that
in the ventral root and nearly twice that at the CNS level
studied. The large amounts of astrocytic tissue in the TZ may
be related to the high packing density of nodes. It may function
to regulate extracellular ionic concentrations in the TZ and to
maintain a stable ionic environment for the transitional nodes.
127. Fujino, Y.; Koyama, N.; Yokota, T. Differential distribution of three
types of nociceptive neurons within the caudal bulbar reticular
formation in the cat. Brain-Res. 1996 Apr 9; 715(1-2): 225-9;
ISSN: 0006-8993.
NETHERLANDS. Nociceptive neurons within the reticular
formation (RF) caudal to the obex were studied. 197 units
recorded from the lateral part of subnucleus reticularis
ventralis had receptive fields in the head, 72 units recorded
from the medial RF in the body, and 160 units recorded from
the middle third of RF in the head and body. About half of the
units tested were antidromically excited by stimulation of
nucleus centralis lateralis.
128. Fujino, Y.; Koyama, N.; Yokota, T. Differential distribution of three
types of nociceptive neurons within the caudal bulbar reticular
formation in the cat. Brain-Res. 1996 Apr 9; 715(1-2): 225-9;
ISSN: 0006-8993.
NETHERLANDS. Nociceptive neurons within the reticular
formation (RF) caudal to the obex were studied. 197 units
recorded from the lateral part of subnucleus reticularis
ventralis had receptive fields in the head, 72 units recorded
from the medial RF in the body, and 160 units recorded from
the middle third of RF in the head and body. About half of the
units tested were antidromically excited by stimulation of
nucleus centralis lateralis.
129. Fujita, K.; Ando, M.; Yamauchi, M.; Nagata, Y.; Honda, M. Alteration
of transglutaminase activity in rat and human spinal cord
after neuronal degeneration. Neurochem-Res. 1995 Oct; 20(10):
1195-201; ISSN: 0364-3190.
UNITED-STATES. We measured the activity of
transglutaminase (TG), a Ca(2+)-dependent enzyme and a
biochemical marker of cell degeneration, in the adult rat
spinal cord after unilateral occlusion of a branch of the dorsal
spinal artery, and compared it to the enzyme activity in the
tissue on the contralateral side without ischemic damage. The
affected half of the spinal cord showed a significant rise in
intrinsic (endogenous) TG activity one day after ischemic
insult while no apparent morphological changes were observed
in the tissue. However, the enzymic activity on the affected
side gradually decreased to reach the level in the non-affected
tissue, accompanying severe degeneration of neuronal cells at
7 days after the surgery, then it declined to nearly half the
level in the intact tissue 30 days after the operation. We also
determined the TG activity in transverse sections of the
human spinal cord obtained at autopsy from 5 amyotrophic
lateral sclerosis (ALS) and 9 non-ALS patients. TG activity in
thoracic and lumbar cords was markedly low in ALS patients
not only in ventral and lateral regions but also in the dorsal
portion. These findings imply that the reduced TG activity in
the ALS spinal cord is one of the characteristic features of the
disease reflecting exhaustion of the enzyme in the tissue
resulting from degeneration of the spinal neurons through
cross-linkage of soluble intraneuronal cytoplasmic proteins..
EC 2.3.2.13.
130. Fujita, K.; Ando, M.; Yamauchi, M.; Nagata, Y.; Honda, M. Alteration
of transglutaminase activity in rat and human spinal cord
after neuronal degeneration. Neurochem-Res. 1995 Oct; 20(10):
1195-201; ISSN: 0364-3190.
UNITED-STATES. We measured the activity of
transglutaminase (TG), a Ca(2+)-dependent enzyme and a
biochemical marker of cell degeneration, in the adult rat
spinal cord after unilateral occlusion of a branch of the dorsal
spinal artery, and compared it to the enzyme activity in the
tissue on the contralateral side without ischemic damage. The
affected half of the spinal cord showed a significant rise in
intrinsic (endogenous) TG activity one day after ischemic
insult while no apparent morphological changes were observed
in the tissue. However, the enzymic activity on the affected
side gradually decreased to reach the level in the non-affected
tissue, accompanying severe degeneration of neuronal cells at
7 days after the surgery, then it declined to nearly half the
level in the intact tissue 30 days after the operation. We also
determined the TG activity in transverse sections of the
human spinal cord obtained at autopsy from 5 amyotrophic
lateral sclerosis (ALS) and 9 non-ALS patients. TG activity in
thoracic and lumbar cords was markedly low in ALS patients
not only in ventral and lateral regions but also in the dorsal
portion. These findings imply that the reduced TG activity in
the ALS spinal cord is one of the characteristic features of the
disease reflecting exhaustion of the enzyme in the tissue
resulting from degeneration of the spinal neurons through
cross-linkage of soluble intraneuronal cytoplasmic proteins..
EC 2.3.2.13.
131. Garrison, D. W.; Foreman, R. D. Effects of transcutaneous
electrical nerve stimulation (TENS) on spontaneous and
noxiously evoked dorsal horn cell activity in cats with
transected spinal cords. Neurosci-Lett. 1996 Sep 27; 216(2):
125-8; ISSN: 0304-3940.
IRELAND. Effects of transcutaneous electrical nerve
stimulation (TENS) on spontaneous and noxiously evoked dorsal
horn neurons were studied in alpha-chloralose anesthetized
cats after spinal cords had been transected at the T12
segment. Previous work in cats with intact cords showed that
TENS applications to somatic receptive fields could
significantly reduce and maintain decreased dorsal horn cell
activity. The purpose of this study was to determine if
supraspinal mechanisms were involved with the initial
reduction of dorsal horn cell activity during TENS applications.
Extracellular action potentials of dorsal horn neurons were
recorded in the absence of supraspinal influences. The results
demonstrated that spontaneously and noxiously evoked cell
activities were reduced significantly during TENS and no
significant difference was found between pre-TENS control
activity and post-TENS application cell activity. This
information implies that initial gating (reduction cell
activity), which occurs during TENS applications, is due to a
segmental effect.
132. Garrison, D. W.; Foreman, R. D. Effects of transcutaneous
electrical nerve stimulation (TENS) on spontaneous and
noxiously evoked dorsal horn cell activity in cats with
transected spinal cords. Neurosci-Lett. 1996 Sep 27; 216(2):
125-8; ISSN: 0304-3940.
IRELAND. Effects of transcutaneous electrical nerve
stimulation (TENS) on spontaneous and noxiously evoked dorsal
horn neurons were studied in alpha-chloralose anesthetized
cats after spinal cords had been transected at the T12
segment. Previous work in cats with intact cords showed that
TENS applications to somatic receptive fields could
significantly reduce and maintain decreased dorsal horn cell
activity. The purpose of this study was to determine if
supraspinal mechanisms were involved with the initial
reduction of dorsal horn cell activity during TENS applications.
Extracellular action potentials of dorsal horn neurons were
recorded in the absence of supraspinal influences. The results
demonstrated that spontaneously and noxiously evoked cell
activities were reduced significantly during TENS and no
significant difference was found between pre-TENS control
activity and post-TENS application cell activity. This
information implies that initial gating (reduction cell
activity), which occurs during TENS applications, is due to a
segmental effect.
133. Gebber, G. L.; Zhong, S.; Paitel, Y. Bispectral analysis of complex
patterns of sympathetic nerve discharge. Am-J-Physiol. 1996
Nov; 271(5 Pt 2): R1173-85; ISSN: 0002-9513.
UNITED-STATES. Bispectral analysis was used to demonstrate
quadratic nonlinear coupling (i.e., phase locking) of different
frequency components in inferior cardiac sympathetic nerve
discharge (SND) of urethan-anesthetized rats. The complex
patterns of SND analyzed included mixtures of 1) the cardiac-
related and 10-Hz rhythms, 2) the 10-Hz rhythm and irregular
2-to 6-Hz oscillations, and 3) the 10-Hz rhythm and a lower
frequency non-cardiac-related rhythm near 4 Hz. In some
cases, the bicoherence function (normalized bispectrum)
showed no phase locking of these frequency components. Cases
of nil bicoherence are equated with linear superposition of
frequency components, which implies the existence of
multiple and noninteractive central circuits. Increased
complexity of SND was observed in other cases, as evidenced
by significant phase locking of different frequency components
with or without frequency locking. Frequency locking (higher
frequency rhythm is a multiple of lower) was confirmed by
constructing Lissajous orbital plots showing covariation of
voltages in selectively filtered bands of SND. We equate
frequency locking with nonlinear coupling of the central
generators of different sympathetic nerve rhythms and phase
locking without frequency locking possibly with nonlinearities
arising at levels below noncoupled central rhythm generators.
134. Gebber, G. L.; Zhong, S.; Paitel, Y. Bispectral analysis of complex
patterns of sympathetic nerve discharge. Am-J-Physiol. 1996
Nov; 271(5 Pt 2): R1173-85; ISSN: 0002-9513.
UNITED-STATES. Bispectral analysis was used to demonstrate
quadratic nonlinear coupling (i.e., phase locking) of different
frequency components in inferior cardiac sympathetic nerve
discharge (SND) of urethan-anesthetized rats. The complex
patterns of SND analyzed included mixtures of 1) the cardiac-
related and 10-Hz rhythms, 2) the 10-Hz rhythm and irregular
2-to 6-Hz oscillations, and 3) the 10-Hz rhythm and a lower
frequency non-cardiac-related rhythm near 4 Hz. In some
cases, the bicoherence function (normalized bispectrum)
showed no phase locking of these frequency components. Cases
of nil bicoherence are equated with linear superposition of
frequency components, which implies the existence of
multiple and noninteractive central circuits. Increased
complexity of SND was observed in other cases, as evidenced
by significant phase locking of different frequency components
with or without frequency locking. Frequency locking (higher
frequency rhythm is a multiple of lower) was confirmed by
constructing Lissajous orbital plots showing covariation of
voltages in selectively filtered bands of SND. We equate
frequency locking with nonlinear coupling of the central
generators of different sympathetic nerve rhythms and phase
locking without frequency locking possibly with nonlinearities
arising at levels below noncoupled central rhythm generators.
135. Georgopoulos, A. P. On the translation of directional motor
cortical commands to activation of muscles via spinal
interneuronal systems. Brain-Res-Cogn-Brain-Res. 1996 Mar;
3(2): 151-5; ISSN: 0926-6410.
NETHERLANDS. I discuss in this paper some of the neural
mechanisms by which directional motor cortical commands
could be potentially translated into multi-muscle activations
to generate a directed force (and initial movement) in space.
Specifically, I review the results of recent studies in the
motor cortex of monkeys and the spinal cord of the frog, and
propose a possible mechanism by which these results could be
formally connected. It is suggested that spinal mechanisms of
the kind described in the spinal frog could serve as substrates
for the operation of directionally tuned motor cortical activity
to produce an appropriately directed motor output by the limb.
136. Georgopoulos, A. P. On the translation of directional motor
cortical commands to activation of muscles via spinal
interneuronal systems. Brain-Res-Cogn-Brain-Res. 1996 Mar;
3(2): 151-5; ISSN: 0926-6410.
NETHERLANDS. I discuss in this paper some of the neural
mechanisms by which directional motor cortical commands
could be potentially translated into multi-muscle activations
to generate a directed force (and initial movement) in space.
Specifically, I review the results of recent studies in the
motor cortex of monkeys and the spinal cord of the frog, and
propose a possible mechanism by which these results could be
formally connected. It is suggested that spinal mechanisms of
the kind described in the spinal frog could serve as substrates
for the operation of directionally tuned motor cortical activity
to produce an appropriately directed motor output by the limb.
137. Gerin, C.; Privat, A. Evaluation of the function of microdialysis
probes permanently implanted into the rat CNS and coupled to
an on-line HPLC system of analysis. J-Neurosci-Methods. 1996
Jun; 66(2): 81-92; ISSN: 0165-0270.
NETHERLANDS. The aim of the microdialysis technique is to
reflect as closely as possible the status and fluctuations of
substances contained in the extracellular space. Most often,
microdialysis is performed with repetitively implanted
probes. We have recently devised an experimental set-up which
allows microdialysis to be performed in the spinal cord of
unrestrained rats through chronically permanently implanted
probes. In the present study, we have compared the in vitro
recovery of a non-biogenic amine (DHBA) and of 5-HT, and the
in vivo recovery of the former. Thus, we could extrapolate the
in vivo recovery of endogenous 5-HT released. Moreover, we
have found that the recovery does not vary irrespective of
whether the animal is at rest or performing sustained physical
exercise, and that it also remains stable with time, from 8 to
36 days after permanent implantation of the probe. We
conclude that this simple method can be applied to standard
experiments of microdialysis, and thus allow one to measure
the actual rate of recovery for a given probe. Moreover, it
permits control of the stability of dialysis parameters with
time for long-term permanently implanted probes.. 37491-68-
2; 50-67-9; 51-61-6.
138. Gerin, C.; Privat, A. Evaluation of the function of microdialysis
probes permanently implanted into the rat CNS and coupled to
an on-line HPLC system of analysis. J-Neurosci-Methods. 1996
Jun; 66(2): 81-92; ISSN: 0165-0270.
NETHERLANDS. The aim of the microdialysis technique is to
reflect as closely as possible the status and fluctuations of
substances contained in the extracellular space. Most often,
microdialysis is performed with repetitively implanted
probes. We have recently devised an experimental set-up which
allows microdialysis to be performed in the spinal cord of
unrestrained rats through chronically permanently implanted
probes. In the present study, we have compared the in vitro
recovery of a non-biogenic amine (DHBA) and of 5-HT, and the
in vivo recovery of the former. Thus, we could extrapolate the
in vivo recovery of endogenous 5-HT released. Moreover, we
have found that the recovery does not vary irrespective of
whether the animal is at rest or performing sustained physical
exercise, and that it also remains stable with time, from 8 to
36 days after permanent implantation of the probe. We
conclude that this simple method can be applied to standard
experiments of microdialysis, and thus allow one to measure
the actual rate of recovery for a given probe. Moreover, it
permits control of the stability of dialysis parameters with
time for long-term permanently implanted probes.. 37491-68-
2; 50-67-9; 51-61-6.
139. Goehler, L. E.; Finger, T. E. Visceral afferent and efferent columns
in the spinal cord of the teleost, Ictalurus punctatus. J-Comp-
Neurol. 1996 Jul 29; 371(3): 437-47; ISSN: 0021-9967.
UNITED-STATES. In tetrapod vertebrates, neural circuitries
subserving visceral and somatic reflexes are each represented
in distinct columns of cells within the gray area of the spinal
cord. To determine the location of visceral elements of the
spinal cord of a teleost fish, crystals of the carbocyanine dye
1,1'dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (DiI),
were placed on either the abdominal sympathetic (mesenteric)
nerves, the coeliac ganglia, or on the rostral three somatic
spinal nerves, in fixed specimens of the channel catfish,
Ictalurus punctatus. In fish in which DiI had been placed on the
mesenteric nerves, labeled fibers coursed along the lateral
margin of the dorsal horn within the first and second spinal
segments, and appeared to terminate in a region at the base of
the dorsal horn. In contrast, when DiI crystals were placed on
the somatic spinal nerves, labeled primary afferents
terminated in the dorsalmost two thirds of the dorsal horn, as
well as in ventral and ventromedial areas of the medial
funicular nuclear complex. Labeled somata (motor neurons)
were situated in the ventral horn. When DiI crystals were
placed bilaterally on the coeliac ganglia, labeled piriform and
fusiform preganglionic neurons occurred in intermediate
positions adjacent to the central canal, corresponding to the
paracentral nucleus of Herrick, and in the lateral funiculus.
These results demonstrate that somatic and visceral afferent
and efferent functional columns are distinct in a teleost fish
as they are in amniote vertebrates.. 0; 0; 40957-95-7.
140. Goehler, L. E.; Finger, T. E. Visceral afferent and efferent columns
in the spinal cord of the teleost, Ictalurus punctatus. J-Comp-
Neurol. 1996 Jul 29; 371(3): 437-47; ISSN: 0021-9967.
UNITED-STATES. In tetrapod vertebrates, neural circuitries
subserving visceral and somatic reflexes are each represented
in distinct columns of cells within the gray area of the spinal
cord. To determine the location of visceral elements of the
spinal cord of a teleost fish, crystals of the carbocyanine dye
1,1'dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (DiI),
were placed on either the abdominal sympathetic (mesenteric)
nerves, the coeliac ganglia, or on the rostral three somatic
spinal nerves, in fixed specimens of the channel catfish,
Ictalurus punctatus. In fish in which DiI had been placed on the
mesenteric nerves, labeled fibers coursed along the lateral
margin of the dorsal horn within the first and second spinal
segments, and appeared to terminate in a region at the base of
the dorsal horn. In contrast, when DiI crystals were placed on
the somatic spinal nerves, labeled primary afferents
terminated in the dorsalmost two thirds of the dorsal horn, as
well as in ventral and ventromedial areas of the medial
funicular nuclear complex. Labeled somata (motor neurons)
were situated in the ventral horn. When DiI crystals were
placed bilaterally on the coeliac ganglia, labeled piriform and
fusiform preganglionic neurons occurred in intermediate
positions adjacent to the central canal, corresponding to the
paracentral nucleus of Herrick, and in the lateral funiculus.
These results demonstrate that somatic and visceral afferent
and efferent functional columns are distinct in a teleost fish
as they are in amniote vertebrates.. 0; 0; 40957-95-7.
141. Gonzalez, A.; Munoz, A.; Munoz, M.; Marin, O.; Arevalo, R.; Porteros,
A.; Alonso, J. R. Nitric oxide synthase in the brain of a urodele
amphibian (Pleurodeles waltl) and its relation to
catecholaminergic neuronal structures. Brain-Res. 1996 Jul
15; 727(1-2): 49-64; ISSN: 0006-8993.
NETHERLANDS. The neuronal structures with NADPH-
diaphorase activity and nitric oxide synthase (NOS)
immunoreactivity have been studied in the brain of the urodele
amphibian Pleurodeles waltl by means of histochemical and
immunocytochemical techniques. Both approaches resulted in
the selective labeling of the same neurons and fiber tracts in
the brain, except for the primary olfactory fibers that did not
stain for NOS but were positive for NADPH-diaphorase. NOS-
containing neurons were found in the olfactory bulbs, pallial
regions, septum, caudal striatum, amygdala and preoptic area.
Only a few diencephalic cells were labeled in the posterior
tubercle and ventral hypothalamus. In the brainstem, abundant
cells were labeled in the tectum, mesencephalic tegmentum
and isthmic region. The most conspicuous cell population was
found in the isthmic-pretrigeminal region. Particularly well
stained cells were distributed throughout the rhombencephalon
in areas related to the descending trigeminal tract, solitary
tract, raphe nucleus and the mid-caudal reticular formation. In
the cervical spinal cord, NOS-containing cells were present in
the dorsal, intermediate and ventral grey fields. Cells in the
preoptic, postotic and dorsal root ganglia were also labeled.
Double labeling techniques revealed an extensive
codistribution of neurons with NOS and catecholamines in the
urodele brain but actual colocalization in the same cells was
never observed. The organization of the central systems in
urodeles with NOS appears to share many features not only
with other anamniotes but also with amniotes.. EC 1.14.13.39;
EC 1.14.16.2; EC 1.6.99.1.
142. Gonzalez, A.; Munoz, A.; Munoz, M.; Marin, O.; Arevalo, R.; Porteros,
A.; Alonso, J. R. Nitric oxide synthase in the brain of a urodele
amphibian (Pleurodeles waltl) and its relation to
catecholaminergic neuronal structures. Brain-Res. 1996 Jul
15; 727(1-2): 49-64; ISSN: 0006-8993.
NETHERLANDS. The neuronal structures with NADPH-
diaphorase activity and nitric oxide synthase (NOS)
immunoreactivity have been studied in the brain of the urodele
amphibian Pleurodeles waltl by means of histochemical and
immunocytochemical techniques. Both approaches resulted in
the selective labeling of the same neurons and fiber tracts in
the brain, except for the primary olfactory fibers that did not
stain for NOS but were positive for NADPH-diaphorase. NOS-
containing neurons were found in the olfactory bulbs, pallial
regions, septum, caudal striatum, amygdala and preoptic area.
Only a few diencephalic cells were labeled in the posterior
tubercle and ventral hypothalamus. In the brainstem, abundant
cells were labeled in the tectum, mesencephalic tegmentum
and isthmic region. The most conspicuous cell population was
found in the isthmic-pretrigeminal region. Particularly well
stained cells were distributed throughout the rhombencephalon
in areas related to the descending trigeminal tract, solitary
tract, raphe nucleus and the mid-caudal reticular formation. In
the cervical spinal cord, NOS-containing cells were present in
the dorsal, intermediate and ventral grey fields. Cells in the
preoptic, postotic and dorsal root ganglia were also labeled.
Double labeling techniques revealed an extensive
codistribution of neurons with NOS and catecholamines in the
urodele brain but actual colocalization in the same cells was
never observed. The organization of the central systems in
urodeles with NOS appears to share many features not only
with other anamniotes but also with amniotes.. EC 1.14.13.39;
EC 1.14.16.2; EC 1.6.99.1.
143. Goo, Y. S.; Kim, S. J.; Lim, W.; Kim, J. Depressor pathway involved
in somatosympathetic reflex in cats. Neurosci-Lett. 1996 Jan
26; 203(3): 187-90; ISSN: 0304-3940.
IRELAND. The present study aimed to identify direct
vasodepressor pathways from the rostral ventrolateral
medulla (RVLM) to the spinal cord and their role in mediation
of somatosympathetic reflexes. Vasopressor and depressor
areas were identified by stimulating various sites of RVLM
electrically and/or chemically in anesthetized cats. Electrical
lesions on the pressor areas abolished the pressor response
evoked by peripheral C-fiber activation while the depressor
response remained. Electrical lesions on the depressor areas
decreased the depressor response evoked by A delta-fiber
stimulation. To characterize the neurons involved, 17
medullospinal sympathetic neurons were identified
electrophysiologically. While most of them were
sympathoexcitatory, three medullospinal tract cells were
found to be sympathoinhibitory neurons. From these results we
concluded that a minor group of neurons in the RVLM is
sympathoinhibitory and is involved in mediation of
somatosympathetic depressor response.
144. Goo, Y. S.; Kim, S. J.; Lim, W.; Kim, J. Depressor pathway involved
in somatosympathetic reflex in cats. Neurosci-Lett. 1996 Jan
26; 203(3): 187-90; ISSN: 0304-3940.
IRELAND. The present study aimed to identify direct
vasodepressor pathways from the rostral ventrolateral
medulla (RVLM) to the spinal cord and their role in mediation
of somatosympathetic reflexes. Vasopressor and depressor
areas were identified by stimulating various sites of RVLM
electrically and/or chemically in anesthetized cats. Electrical
lesions on the pressor areas abolished the pressor response
evoked by peripheral C-fiber activation while the depressor
response remained. Electrical lesions on the depressor areas
decreased the depressor response evoked by A delta-fiber
stimulation. To characterize the neurons involved, 17
medullospinal sympathetic neurons were identified
electrophysiologically. While most of them were
sympathoexcitatory, three medullospinal tract cells were
found to be sympathoinhibitory neurons. From these results we
concluded that a minor group of neurons in the RVLM is
sympathoinhibitory and is involved in mediation of
somatosympathetic depressor response.
145. Gossard, J. P.; Floeter, M. K.; Degtyarenko, A. M.; Simon, E. S.;
Burke, R. E. Disynaptic vestibulospinal and reticulospinal
excitation in cat lumbosacral motoneurons: modulation during
fictive locomotion. Exp-Brain-Res. 1996 May; 109(2): 277-88;
ISSN: 0014-4819.
GERMANY. This study compares some characteristics of the
disynaptic excitatory pathways from the lateral vestibular
nucleus (LVN) and medial longitudinal fasciculus (MLF) to
lumbosacral alpha-motoneurons in the decerebrate cat. We
used the spatial facilitation technique to test whether
disynaptic LVN and MLF excitatory postsynaptic potentials
(EPSPs) are produced by common last-order interneurons in the
lumbosacral segments of the spinal cord. Of 77 motoneurons
examined, 26 exhibited disynaptic EPSPs from both
supraspinal sources. No spatial facilitation was found between
LVN and MLF EPSPs in 21 of 24 cells that were adequately
tested. In 3 of 23 cells (all flexor motoneurons), some spatial
facilitation was found in some but not all trials. These
observations suggest that stimulation of the LVN and MLF
produces disynaptic EPSPs in motoneurons through largely
separate populations of last-order interneurons. Disynaptic
MLF and LVN EPSPs showed parallel patterns of modulation
during fictive locomotion. Maximal disynaptic EPSP amplitudes
occurred during the phase of the step cycle when the recorded
motoneuron, whether flexor or extensor, exhibited depolarizing
locomotor drive potentials and the corresponding muscle nerve
was active. These observations, taken together, suggest that
disynaptic LVN and MLF EPSPs are produced in motoneurons by
at least four separate populations of segmental last-order
excitatory interneurons, with separate populations projecting
to flexor versus extensor cells. The results also suggest that
the modulation of the disynaptic EPSPs during fictive
locomotion is mainly due to premotoneuronal convergence of
input from the respective descending systems and from the
segmental central pattern generator for locomotion onto
common interneurons.
146. Gossard, J. P.; Floeter, M. K.; Degtyarenko, A. M.; Simon, E. S.;
Burke, R. E. Disynaptic vestibulospinal and reticulospinal
excitation in cat lumbosacral motoneurons: modulation during
fictive locomotion. Exp-Brain-Res. 1996 May; 109(2): 277-88;
ISSN: 0014-4819.
GERMANY. This study compares some characteristics of the
disynaptic excitatory pathways from the lateral vestibular
nucleus (LVN) and medial longitudinal fasciculus (MLF) to
lumbosacral alpha-motoneurons in the decerebrate cat. We
used the spatial facilitation technique to test whether
disynaptic LVN and MLF excitatory postsynaptic potentials
(EPSPs) are produced by common last-order interneurons in the
lumbosacral segments of the spinal cord. Of 77 motoneurons
examined, 26 exhibited disynaptic EPSPs from both
supraspinal sources. No spatial facilitation was found between
LVN and MLF EPSPs in 21 of 24 cells that were adequately
tested. In 3 of 23 cells (all flexor motoneurons), some spatial
facilitation was found in some but not all trials. These
observations suggest that stimulation of the LVN and MLF
produces disynaptic EPSPs in motoneurons through largely
separate populations of last-order interneurons. Disynaptic
MLF and LVN EPSPs showed parallel patterns of modulation
during fictive locomotion. Maximal disynaptic EPSP amplitudes
occurred during the phase of the step cycle when the recorded
motoneuron, whether flexor or extensor, exhibited depolarizing
locomotor drive potentials and the corresponding muscle nerve
was active. These observations, taken together, suggest that
disynaptic LVN and MLF EPSPs are produced in motoneurons by
at least four separate populations of segmental last-order
excitatory interneurons, with separate populations projecting
to flexor versus extensor cells. The results also suggest that
the modulation of the disynaptic EPSPs during fictive
locomotion is mainly due to premotoneuronal convergence of
input from the respective descending systems and from the
segmental central pattern generator for locomotion onto
common interneurons.
147. Greer, J. J.; al Zubaidy, Z.; Carter, J. E. Thyrotropin-releasing
hormone stimulates perinatal rat respiration in vitro. Am-J-
Physiol. 1996 Nov; 271(5 Pt 2): R1160-4; ISSN: 0002-9513.
UNITED-STATES. In the present study, we test whether
thyrotropin-releasing hormone (TRH) stimulates respiratory
frequency in perinatal rats by acting at regions of the medulla
responsible for respiratory rhythmogenesis, the pre-Botzinger
complex. We also test whether TRH stimulates respiration in
the fetal rat at a time shortly after the inception of
respiratory rhythmogenesis [embryonic days (E) 17-18]. Two in
vitro experimental models were utilized: the isolated brain
stem-spinal cord preparation from fetal (E17-E18) and
neonatal [postnatal days (P) 0-2] rats and the medullary slice
preparation isolated from neonatal rats (P1-P2). Bath
application of TRH caused a dose-dependent, reversible
increase (maximum increase approximately 60%) in the
frequency of respiratory rhythmic neural discharge generated
by brain stem-spinal cord [half-maximal effective
concentration (EC50) approximately 9 nM] and medullary slice
(EC50 approximately 2.5 nM) neonatal rat preparations.
Pressure injection of TRH unilaterally into the region of the
pre-Botzinger complex of the neonatal medullary slice caused
an approximately 28% increase in the frequency of respiratory
discharge. Application of TRH to the medium bathing fetal rat
brain stem-spinal cord preparations caused an approximately
threefold increase in respiratory discharge frequency. We
conclude that TRH stimulates respiratory discharge frequency
from the time near inception of respiratory motor discharge
and acts directly at the pre-Botzinger complex.. 24305-27-9.
148. Greer, J. J.; al Zubaidy, Z.; Carter, J. E. Thyrotropin-releasing
hormone stimulates perinatal rat respiration in vitro. Am-J-
Physiol. 1996 Nov; 271(5 Pt 2): R1160-4; ISSN: 0002-9513.
UNITED-STATES. In the present study, we test whether
thyrotropin-releasing hormone (TRH) stimulates respiratory
frequency in perinatal rats by acting at regions of the medulla
responsible for respiratory rhythmogenesis, the pre-Botzinger
complex. We also test whether TRH stimulates respiration in
the fetal rat at a time shortly after the inception of
respiratory rhythmogenesis [embryonic days (E) 17-18]. Two in
vitro experimental models were utilized: the isolated brain
stem-spinal cord preparation from fetal (E17-E18) and
neonatal [postnatal days (P) 0-2] rats and the medullary slice
preparation isolated from neonatal rats (P1-P2). Bath
application of TRH caused a dose-dependent, reversible
increase (maximum increase approximately 60%) in the
frequency of respiratory rhythmic neural discharge generated
by brain stem-spinal cord [half-maximal effective
concentration (EC50) approximately 9 nM] and medullary slice
(EC50 approximately 2.5 nM) neonatal rat preparations.
Pressure injection of TRH unilaterally into the region of the
pre-Botzinger complex of the neonatal medullary slice caused
an approximately 28% increase in the frequency of respiratory
discharge. Application of TRH to the medium bathing fetal rat
brain stem-spinal cord preparations caused an approximately
threefold increase in respiratory discharge frequency. We
conclude that TRH stimulates respiratory discharge frequency
from the time near inception of respiratory motor discharge
and acts directly at the pre-Botzinger complex.. 24305-27-9.
149. Grijalva, I.; Guizar Sahagun, G.; Salgado Ceballos, H.; Ibarra, A.;
Franco Bourland, R.; Espitia, L.; Madrazo, I. Improvement of
host-graft adhesion by enzymatic manipulation of the subacute
spinal cord contusion area in the rat. Transplant-Proc. 1996
Dec; 28(6): 3340-2; ISSN: 0041-1345.
UNITED-STATES. EC 3.2.1.35; EC 3.4.24.-.
150. Grijalva, I.; Guizar Sahagun, G.; Salgado Ceballos, H.; Ibarra, A.;
Franco Bourland, R.; Espitia, L.; Madrazo, I. Improvement of
host-graft adhesion by enzymatic manipulation of the subacute
spinal cord contusion area in the rat. Transplant-Proc. 1996
Dec; 28(6): 3340-2; ISSN: 0041-1345.
UNITED-STATES. EC 3.2.1.35; EC 3.4.24.-.
151. Grubb, B. D.; Riley, R. C.; Hope, P. J.; Pubols, L.; Duggan, A. W. The
burst-like firing of spinal neurons in rats with peripheral
inflammation is reduced by an antagonist of N-methyl-D-
aspartate. Neuroscience. 1996 Oct; 74(4): 1077-86; ISSN:
0306-4522.
UNITED-STATES. Ankle inflammation was induced in rats by
subcutaneous injection of complete Freund's adjuvant and the
firing properties of spinal neurons receiving afferent input
from the inflamed areas were studied four to six days later.
Comparable neurons in normal rats were also studied. In
normal animals the response of neurons to ankle compression
consisted of a brief burst of action potentials followed by
sustained firing during stimulus application. On cessation of
the stimulus there was no prolonged afterdischarge. In rats
with an inflamed ankle, compression of the ankle produced
firing while the stimulus was applied, but with 17 of 22
neurons there was a prolonged (219 +/- 55 s) post-stimulus
afterdischarge. All neurons studied in rats with peripheral
inflammation fired with intermittent bursts of action
potentials, particularly during the afterdischarge and
spontaneous firing. The N-methyl-D-aspartate receptor
antagonist DL-2-amino-5-phosphonopentanoate was ejected
microiontophoretically near the cells studied. The major
effect was a near abolition of bursts present in spontaneous
firing and post-stimulus afterdischarges with a lesser
reduction in firing during stimulus application. Effects on
afterdischarge duration were variable. Since firing in bursts is
known to increase transmitter release at some sites in the
brain, it is proposed that when the relevant spinal neurons fire
in bursts, additional intraspinal pathways are recruited and
this contributes to the expanded receptive fields of neurons
and possibly to the enhanced pain experienced by manipulation
of inflamed peripheral tissues.. 0; 6384-92-5; 76726-92-6.
152. Grubb, B. D.; Riley, R. C.; Hope, P. J.; Pubols, L.; Duggan, A. W. The
burst-like firing of spinal neurons in rats with peripheral
inflammation is reduced by an antagonist of N-methyl-D-
aspartate. Neuroscience. 1996 Oct; 74(4): 1077-86; ISSN:
0306-4522.
UNITED-STATES. Ankle inflammation was induced in rats by
subcutaneous injection of complete Freund's adjuvant and the
firing properties of spinal neurons receiving afferent input
from the inflamed areas were studied four to six days later.
Comparable neurons in normal rats were also studied. In
normal animals the response of neurons to ankle compression
consisted of a brief burst of action potentials followed by
sustained firing during stimulus application. On cessation of
the stimulus there was no prolonged afterdischarge. In rats
with an inflamed ankle, compression of the ankle produced
firing while the stimulus was applied, but with 17 of 22
neurons there was a prolonged (219 +/- 55 s) post-stimulus
afterdischarge. All neurons studied in rats with peripheral
inflammation fired with intermittent bursts of action
potentials, particularly during the afterdischarge and
spontaneous firing. The N-methyl-D-aspartate receptor
antagonist DL-2-amino-5-phosphonopentanoate was ejected
microiontophoretically near the cells studied. The major
effect was a near abolition of bursts present in spontaneous
firing and post-stimulus afterdischarges with a lesser
reduction in firing during stimulus application. Effects on
afterdischarge duration were variable. Since firing in bursts is
known to increase transmitter release at some sites in the
brain, it is proposed that when the relevant spinal neurons fire
in bursts, additional intraspinal pathways are recruited and
this contributes to the expanded receptive fields of neurons
and possibly to the enhanced pain experienced by manipulation
of inflamed peripheral tissues.. 0; 6384-92-5; 76726-92-6.
153. Hayes, T. L.; Lewis, D. A. Magnopyramidal neurons in the anterior
motor speech region. Dendritic features and interhemispheric
comparisons. Arch-Neurol. 1996 Dec; 53(12): 1277-83; ISSN:
0003-9942.
UNITED-STATES. OBJECTIVE: To test the hypothesis that the
larger somal size of layer III magnopyramidal neurons in left
than in right Brodmann area 45 is associated with greater
measures of dendritic arborization in the left hemisphere
neurons. DESIGN: A case series involving postmortem human
brain specimens was used to compare dendritic parameters of
Golgi-impregnated layer III pyramidal neurons in Brodmann
area 45 in the left and right hemispheres. SUBJECTS: A
convenience sample consisting of 9 subjects with no known
neurologic or psychiatric disorders was obtained at autopsy.
MAIN OUTCOME MEASURES: Dendritic parameters of the 10
largest Golgi-impregnated layer III pyramidal neurons were
measured in each hemisphere of each brain using a eutectic
neuron tracing system. The measures examined were somal
size, neuron depth, mean segment length, number of branch
points, maximal branch order, combined dendritic diameter,
total dendritic length, horizontal extent of the dendritic field,
and spine density. The Golgi-impregnated slides were also
compared with Nissl-stained slides from adjacent blocks to
determine the laminar location of the sampled neurons.
RESULTS: Although the mean somal size was greater in the left
than in the right hemisphere, none of the dendritic parameters
examined was larger for the left hemisphere neurons. As
expected, total dendritic length was positively correlated to
somal size (r = 0.43, P < 001) in the left hemisphere. However,
there was no correlation between these parameters in the
right hemisphere (r = 0.02, P = .76). CONCLUSIONS: The
difference between left and right Brodmann area 45
magnopyramidal neurons in the correlation of somal size and
dendritic length provides additional evidence of anatomical
differences between these 2 populations of neurons. However,
the lack of interhemispheric differences in measures of
dendritic arborization suggests that additional factors
contribute significantly to the marked difference in somal
size between the large magnopyramidal neurons in the left and
right hemispheres.
154. Hayes, T. L.; Lewis, D. A. Magnopyramidal neurons in the anterior
motor speech region. Dendritic features and interhemispheric
comparisons. Arch-Neurol. 1996 Dec; 53(12): 1277-83; ISSN:
0003-9942.
UNITED-STATES. OBJECTIVE: To test the hypothesis that the
larger somal size of layer III magnopyramidal neurons in left
than in right Brodmann area 45 is associated with greater
measures of dendritic arborization in the left hemisphere
neurons. DESIGN: A case series involving postmortem human
brain specimens was used to compare dendritic parameters of
Golgi-impregnated layer III pyramidal neurons in Brodmann
area 45 in the left and right hemispheres. SUBJECTS: A
convenience sample consisting of 9 subjects with no known
neurologic or psychiatric disorders was obtained at autopsy.
MAIN OUTCOME MEASURES: Dendritic parameters of the 10
largest Golgi-impregnated layer III pyramidal neurons were
measured in each hemisphere of each brain using a eutectic
neuron tracing system. The measures examined were somal
size, neuron depth, mean segment length, number of branch
points, maximal branch order, combined dendritic diameter,
total dendritic length, horizontal extent of the dendritic field,
and spine density. The Golgi-impregnated slides were also
compared with Nissl-stained slides from adjacent blocks to
determine the laminar location of the sampled neurons.
RESULTS: Although the mean somal size was greater in the left
than in the right hemisphere, none of the dendritic parameters
examined was larger for the left hemisphere neurons. As
expected, total dendritic length was positively correlated to
somal size (r = 0.43, P < 001) in the left hemisphere. However,
there was no correlation between these parameters in the
right hemisphere (r = 0.02, P = .76). CONCLUSIONS: The
difference between left and right Brodmann area 45
magnopyramidal neurons in the correlation of somal size and
dendritic length provides additional evidence of anatomical
differences between these 2 populations of neurons. However,
the lack of interhemispheric differences in measures of
dendritic arborization suggests that additional factors
contribute significantly to the marked difference in somal
size between the large magnopyramidal neurons in the left and
right hemispheres.
155. He, M.; Howe, D. G.; McCarthy, K. D. Oligodendroglial signal
transduction systems are regulated by neuronal contact. J-
Neurochem. 1996 Oct; 67(4): 1491-9; ISSN: 0022-3042.
UNITED-STATES. Previous reports indicate that
oligodendrocytes express signaling systems activated by
classical neurotransmitters. Several signaling systems linked
to mobilization of intracellular calcium have been
demonstrated, and some of these are developmentally lost in
vitro and in vivo. The experiments described here use
oligodendrocyte-neuron cocultures to examine the effects of
neuronal contact on the expression of these signaling
pathways. Neonatal rat cerebral oligodendrocytes in contact
with dorsal root ganglia (DRG) neurites responded to bath
application of histamine, ATP, carbachol, glutamate, or
bradykinin with increases in intracellular Ca2+ concentration.
Similar results were obtained in coculture with superior
cervical ganglia neurons. Preventing neuronal contact by
transection of DRG neurites significantly reduced the
percentage of oligodendrocytes responsive to each ligand, with
the exception of bradykinin responsiveness, which was
unaffected. Oligodendroglia isolated from adult rat spinal cord
were also examined for responsiveness to these neuroligands.
Few isolated adult oligodendroglia were responsive to these
ligands, and coculture with DRG neurons failed to restore
responsiveness. Neuroligand responsiveness was not induced in
oligodendrocytes maintained 8 days in purified culture before
establishment of cocultures. A significant reduction in the
number of neuroligand-responsive oligodendroglia was noted
for histamine, carbachol, glutamate, and ATP after including
tetrodotoxin for the final 6 days of coculture. These results
suggest that both neuronal contact and neuronal activity
contribute to the maintenance of functional neurotransmitter-
activated signaling pathways coupled to mobilization of
intracellular calcium in oligodendrocytes.. 7440-70-2.
156. He, M.; Howe, D. G.; McCarthy, K. D. Oligodendroglial signal
transduction systems are regulated by neuronal contact. J-
Neurochem. 1996 Oct; 67(4): 1491-9; ISSN: 0022-3042.
UNITED-STATES. Previous reports indicate that
oligodendrocytes express signaling systems activated by
classical neurotransmitters. Several signaling systems linked
to mobilization of intracellular calcium have been
demonstrated, and some of these are developmentally lost in
vitro and in vivo. The experiments described here use
oligodendrocyte-neuron cocultures to examine the effects of
neuronal contact on the expression of these signaling
pathways. Neonatal rat cerebral oligodendrocytes in contact
with dorsal root ganglia (DRG) neurites responded to bath
application of histamine, ATP, carbachol, glutamate, or
bradykinin with increases in intracellular Ca2+ concentration.
Similar results were obtained in coculture with superior
cervical ganglia neurons. Preventing neuronal contact by
transection of DRG neurites significantly reduced the
percentage of oligodendrocytes responsive to each ligand, with
the exception of bradykinin responsiveness, which was
unaffected. Oligodendroglia isolated from adult rat spinal cord
were also examined for responsiveness to these neuroligands.
Few isolated adult oligodendroglia were responsive to these
ligands, and coculture with DRG neurons failed to restore
responsiveness. Neuroligand responsiveness was not induced in
oligodendrocytes maintained 8 days in purified culture before
establishment of cocultures. A significant reduction in the
number of neuroligand-responsive oligodendroglia was noted
for histamine, carbachol, glutamate, and ATP after including
tetrodotoxin for the final 6 days of coculture. These results
suggest that both neuronal contact and neuronal activity
contribute to the maintenance of functional neurotransmitter-
activated signaling pathways coupled to mobilization of
intracellular calcium in oligodendrocytes.. 7440-70-2.
157. He, X. L.; Liu, X.; Zhu, B.; Xu, W. D.; Zhang, S. X. [Central mechanism
of an extensive analgesic effect due to strong
electroacupuncture of acupoint on spinal dorsal horn neurons].
Sheng-Li-Hsueh-Pao. 1995 Dec; 47(6): 605-9; ISSN: 0371-
0874.
CHINA. Experiments were performed on male rats. The
responses of dorsal horn convergent neurons in spinal cord
(T12-L1) to noxious stimulation of hind paw were recorded
extracellularly with glass microelectrode. When low intensity
(2 V) electroacupuncture (EA) was used, the nociceptive
responses of convergent neurons were inhibited by EA at
"Zusanli" near noxious stimulation area, but not at "Xiaguan"
far from the area. When intensity (18 V) high than the
threshold of C fibers EA was applied at the far acupoint
"Xiaguan", obvious analgesic effects on convergent neurons
were also produced, showing an extensive analgesic effect of
strong EA at acupoint. This extensive analgesic effect was
abdicated by lesion of nucleus raphe magnus (NRM), but still
persisted to some extent by EA at the same segment acupoint
"Zusanli" with 18 V or 2 V intensity. The results suggest that,
the extensive analgesia of strong EA at far segment acupoint
may be mainly mediated by noxious stimulation through NRM, a
negative feedback mechanism modulating pain of supraspinal
cord. The analgesia due to 2 V EA at the same segment
acupoint may be mainly produced by gate control in spinal
cord, but also to some extend by supraspinal cord mechanism.
158. He, X. L.; Liu, X.; Zhu, B.; Xu, W. D.; Zhang, S. X. [Central mechanism
of an extensive analgesic effect due to strong
electroacupuncture of acupoint on spinal dorsal horn neurons].
Sheng-Li-Hsueh-Pao. 1995 Dec; 47(6): 605-9; ISSN: 0371-
0874.
CHINA. Experiments were performed on male rats. The
responses of dorsal horn convergent neurons in spinal cord
(T12-L1) to noxious stimulation of hind paw were recorded
extracellularly with glass microelectrode. When low intensity
(2 V) electroacupuncture (EA) was used, the nociceptive
responses of convergent neurons were inhibited by EA at
"Zusanli" near noxious stimulation area, but not at "Xiaguan"
far from the area. When intensity (18 V) high than the
threshold of C fibers EA was applied at the far acupoint
"Xiaguan", obvious analgesic effects on convergent neurons
were also produced, showing an extensive analgesic effect of
strong EA at acupoint. This extensive analgesic effect was
abdicated by lesion of nucleus raphe magnus (NRM), but still
persisted to some extent by EA at the same segment acupoint
"Zusanli" with 18 V or 2 V intensity. The results suggest that,
the extensive analgesia of strong EA at far segment acupoint
may be mainly mediated by noxious stimulation through NRM, a
negative feedback mechanism modulating pain of supraspinal
cord. The analgesia due to 2 V EA at the same segment
acupoint may be mainly produced by gate control in spinal
cord, but also to some extend by supraspinal cord mechanism.
159. Hernandez Sanchez, C.; Wood, T. L.; LeRoith, D. Developmental and
tissue-specific sulfonylurea receptor gene expression.
Endocrinology. 1997 Feb; 138(2): 705-11; ISSN: 0013-7227.
UNITED-STATES. We have studied the developmental
regulation of mouse sulfonylurea receptor (SUR) gene
expression throughout several embryonic stages as well as in
the adult mouse. To this end we used a 229-bp mouse
complementary DNA corresponding to the 3'-end of the SUR
gene for in situ hybridization and solution
hybridization/ribonuclease protection assays. We found that
the SUR gene was expressed as early as embryonic day 12 in
the developing pancreas, heart, and central nervous system.
These tissues maintained significant levels of SUR messenger
RNA (mRNA) throughout development. In addition, SUR mRNA
was detected in the submandibular gland, anterior duodenum,
dorsal root ganglia, lens, retina, and vibrissae by late
developmental stages. SUR mRNA is widely distributed in adult
mouse tissues, with the exception of the liver. In the adult
pancreas, the SUR gene was expressed exclusively in endocrine
tissue. Although significant levels of SUR mRNA were broadly
seen throughout the brain, neurons of the cerebellum,
hippocampus, and thalamus had especially high levels of SUR
mRNA. These findings support the idea that the SUR has
important functions in many other tissues in addition to the
islets of the pancreas.. 0; 0; 0; 0; 0.
160. Hernandez Sanchez, C.; Wood, T. L.; LeRoith, D. Developmental and
tissue-specific sulfonylurea receptor gene expression.
Endocrinology. 1997 Feb; 138(2): 705-11; ISSN: 0013-7227.
UNITED-STATES. We have studied the developmental
regulation of mouse sulfonylurea receptor (SUR) gene
expression throughout several embryonic stages as well as in
the adult mouse. To this end we used a 229-bp mouse
complementary DNA corresponding to the 3'-end of the SUR
gene for in situ hybridization and solution
hybridization/ribonuclease protection assays. We found that
the SUR gene was expressed as early as embryonic day 12 in
the developing pancreas, heart, and central nervous system.
These tissues maintained significant levels of SUR messenger
RNA (mRNA) throughout development. In addition, SUR mRNA
was detected in the submandibular gland, anterior duodenum,
dorsal root ganglia, lens, retina, and vibrissae by late
developmental stages. SUR mRNA is widely distributed in adult
mouse tissues, with the exception of the liver. In the adult
pancreas, the SUR gene was expressed exclusively in endocrine
tissue. Although significant levels of SUR mRNA were broadly
seen throughout the brain, neurons of the cerebellum,
hippocampus, and thalamus had especially high levels of SUR
mRNA. These findings support the idea that the SUR has
important functions in many other tissues in addition to the
islets of the pancreas.. 0; 0; 0; 0; 0.
161. Herrero, J. F.; Headley, P. M. Cutaneous responsiveness of lumbar
spinal neurons in awake and halothane-anesthetized sheep. J-
Neurophysiol. 1995 Oct; 74(4): 1549-62; ISSN: 0022-3077.
UNITED-STATES. 1. To compare the responsiveness of lumbar
spinal neurons to peripheral sensory stimuli under normal
physiological conditions and under halothane anesthesia, we
performed a study in sheep that were prepared chronically.
This permitted recordings to be made in the same animals
either when they were awake and free from recent surgery,
drugs, and training and only partially restrained or when they
were anesthetized with halothane. 2. We recorded 261 units in
dorsal and ventral horns under conscious conditions. Of these,
19% had no detectable receptive field (RF) and 44% had
responses dominated by proprioceptive inputs; these units
were not investigated in detail. The remaining 96 neurons
(37%) had clearly defined cutaneous RFs. Of these, most (72%)
had wide-dynamic-range (WDR; convergent, multireceptive)
properties, 19% were low-threshold mechanoreceptive (LTMR),
and 9% were high-threshold mechanoreceptive (HTMR). These
units with cutaneous RFs were investigated in greater detail.
3. The spontaneous activity under these awake conditions was
low (< 4 spikes/s) for nearly all units in all three categories.
The mechanical threshold of the most sensitive (central) part
of the cutaneous RF was assessed with von Frey bristles.
Thresholds were < 5 mN for all LTMR neurons, < 1-30 mN for
WDR neurons, and > 80 mN for HTMR neurons. The size of the
low-threshold cutaneous RFs was significantly larger for WDR
neurons (mean 46 cm2) and HTMR neurons (45 cm2) than for
LTMR neurons (24 cm2). The RFs were distributed all over the
ipsilateral hindlimb. Large RFs were mostly proximal, whereas
small RFs were distributed relatively evenly over the limb. 4.
Recordings were made from a further 165 units while the
animals were under halothane anesthesia. With 86 neurons
having cutaneous peripheral RFs, the proportions having LTMR,
HTMR, or WDR characteristics were very similar to those in
awake animals. Under halothane the ongoing activity of WDR
units was slightly (but significantly) less. The threshold to
von Frey bristle stimulation was significantly higher only for
WDR units, in both dorsal and ventral horns. The mean size of
cutaneous RFs was significantly larger in all classes of units
recorded under halothane anesthesia. For WDR units this was
true for cells in both dorsal and ventral horns. This effect on
mean values was due to a larger proportion of units with very
large fields under anesthesia, particularly in the dorsal horn.
5. Comparison of the data from conscious animals with
published results of acute experiments indicates that acute
recording conditions do not distort the relative distribution
and resting characteristics of these three functional
categories of lumbar spinal neurons as much as might have
been expected. 6. Halothane does not have major effects on the
resting sensory responsiveness of spinal neurons with
cutaneous RFs. The increase in RF area, which contrasts with
most results from acute studies, is likely to be due to a
dampening of descending inhibitory control mechanisms.. 151-
67-7.
162. Herrero, J. F.; Headley, P. M. Cutaneous responsiveness of lumbar
spinal neurons in awake and halothane-anesthetized sheep. J-
Neurophysiol. 1995 Oct; 74(4): 1549-62; ISSN: 0022-3077.
UNITED-STATES. 1. To compare the responsiveness of lumbar
spinal neurons to peripheral sensory stimuli under normal
physiological conditions and under halothane anesthesia, we
performed a study in sheep that were prepared chronically.
This permitted recordings to be made in the same animals
either when they were awake and free from recent surgery,
drugs, and training and only partially restrained or when they
were anesthetized with halothane. 2. We recorded 261 units in
dorsal and ventral horns under conscious conditions. Of these,
19% had no detectable receptive field (RF) and 44% had
responses dominated by proprioceptive inputs; these units
were not investigated in detail. The remaining 96 neurons
(37%) had clearly defined cutaneous RFs. Of these, most (72%)
had wide-dynamic-range (WDR; convergent, multireceptive)
properties, 19% were low-threshold mechanoreceptive (LTMR),
and 9% were high-threshold mechanoreceptive (HTMR). These
units with cutaneous RFs were investigated in greater detail.
3. The spontaneous activity under these awake conditions was
low (< 4 spikes/s) for nearly all units in all three categories.
The mechanical threshold of the most sensitive (central) part
of the cutaneous RF was assessed with von Frey bristles.
Thresholds were < 5 mN for all LTMR neurons, < 1-30 mN for
WDR neurons, and > 80 mN for HTMR neurons. The size of the
low-threshold cutaneous RFs was significantly larger for WDR
neurons (mean 46 cm2) and HTMR neurons (45 cm2) than for
LTMR neurons (24 cm2). The RFs were distributed all over the
ipsilateral hindlimb. Large RFs were mostly proximal, whereas
small RFs were distributed relatively evenly over the limb. 4.
Recordings were made from a further 165 units while the
animals were under halothane anesthesia. With 86 neurons
having cutaneous peripheral RFs, the proportions having LTMR,
HTMR, or WDR characteristics were very similar to those in
awake animals. Under halothane the ongoing activity of WDR
units was slightly (but significantly) less. The threshold to
von Frey bristle stimulation was significantly higher only for
WDR units, in both dorsal and ventral horns. The mean size of
cutaneous RFs was significantly larger in all classes of units
recorded under halothane anesthesia. For WDR units this was
true for cells in both dorsal and ventral horns. This effect on
mean values was due to a larger proportion of units with very
large fields under anesthesia, particularly in the dorsal horn.
5. Comparison of the data from conscious animals with
published results of acute experiments indicates that acute
recording conditions do not distort the relative distribution
and resting characteristics of these three functional
categories of lumbar spinal neurons as much as might have
been expected. 6. Halothane does not have major effects on the
resting sensory responsiveness of spinal neurons with
cutaneous RFs. The increase in RF area, which contrasts with
most results from acute studies, is likely to be due to a
dampening of descending inhibitory control mechanisms.. 151-
67-7.
163. Hesselink, J. R. In the area of MR imaging, do we still need to
teach our residents in neuroradiology how to perform the
lateral cervical C1-C2 puncture to reach the intrathecal
space? AJR-Am-J-Roentgenol. 1996 Nov; 167(5): 1338-9;
ISSN: 0361-803X.
UNITED-STATES.
164. Hesselink, J. R. In the area of MR imaging, do we still need to
teach our residents in neuroradiology how to perform the
lateral cervical C1-C2 puncture to reach the intrathecal
space? AJR-Am-J-Roentgenol. 1996 Nov; 167(5): 1338-9;
ISSN: 0361-803X.
UNITED-STATES.
165. Hill, B. D.; Prior, H.; Blakemore, W. F.; Black, P. F. A study of
pathology of a bovine primary peripheral myelinopathy with
features of tomaculous neuropathy. Acta-Neuropathol-Berl.
1996; 91(5): 545-8; ISSN: 0001-6322.
GERMANY. Cases of a bovine neuropathy are reported in which
peripheral nerves show "sausage-shaped" thickenings of the
myelin sheaths at different sites of the internode. Clinical
signs of dysphagia and chronic rumenal bloat developed after
weaning which were attributable to bilateral vagus nerve
degeneration. Trunks of the sciatic nerves and brachial
plexuses were similarly affected with the animal adopting a
weak shuffling gait. Affected animals were the progeny of
sire-daughter matings. The lesions are similar to those seen in
the tomaculous neuropathies of man. The present study is
believed to be the first report of this lesion occurring in
domestic animals.
166. Hill, B. D.; Prior, H.; Blakemore, W. F.; Black, P. F. A study of
pathology of a bovine primary peripheral myelinopathy with
features of tomaculous neuropathy. Acta-Neuropathol-Berl.
1996; 91(5): 545-8; ISSN: 0001-6322.
GERMANY. Cases of a bovine neuropathy are reported in which
peripheral nerves show "sausage-shaped" thickenings of the
myelin sheaths at different sites of the internode. Clinical
signs of dysphagia and chronic rumenal bloat developed after
weaning which were attributable to bilateral vagus nerve
degeneration. Trunks of the sciatic nerves and brachial
plexuses were similarly affected with the animal adopting a
weak shuffling gait. Affected animals were the progeny of
sire-daughter matings. The lesions are similar to those seen in
the tomaculous neuropathies of man. The present study is
believed to be the first report of this lesion occurring in
domestic animals.
167. Hogan, Q. H.; Abram, S. E. Neural blockade for diagnosis and
prognosis. A review [see comments]. Anesthesiology. 1997 Jan;
86(1): 216-41; ISSN: 0003-3022.
Note: Comment in: Anesthesiology 1997 Jan;86(1 ):4-6.
UNITED-STATES. On the basis of the published material
reviewed above, we conclude that there are many limitations
that weaken the theoretic basis for neural blockade as a
diagnostic or prognostic tool. In addition, these procedures in
general lack thorough documentation of clinical usefulness.
Reasonable employment of diagnostic neural blockade,
therefore, requires not only care in technique and confirmation
of effects, but also caution in interpretation and application
of the results. This critical evaluation needs to be tempered,
however, by two further observations. Experienced and
observant clinicians have found these procedures may, on
certain occasions, provide information that is helpful in
guiding subsequent therapy, so we should not be in haste to
dismiss the accumulated judgment of practitioners. Finally,
the confusion and complexity that typifies diagnosis in chronic
pain may justify the selective use of diagnostic blocks that
make anatomic and physiologic sense, even if their validity is
incompletely proved.. 0.
168. Hogan, Q. H.; Abram, S. E. Neural blockade for diagnosis and
prognosis. A review [see comments]. Anesthesiology. 1997 Jan;
86(1): 216-41; ISSN: 0003-3022.
Note: Comment in: Anesthesiology 1997 Jan;86(1 ):4-6.
UNITED-STATES. On the basis of the published material
reviewed above, we conclude that there are many limitations
that weaken the theoretic basis for neural blockade as a
diagnostic or prognostic tool. In addition, these procedures in
general lack thorough documentation of clinical usefulness.
Reasonable employment of diagnostic neural blockade,
therefore, requires not only care in technique and confirmation
of effects, but also caution in interpretation and application
of the results. This critical evaluation needs to be tempered,
however, by two further observations. Experienced and
observant clinicians have found these procedures may, on
certain occasions, provide information that is helpful in
guiding subsequent therapy, so we should not be in haste to
dismiss the accumulated judgment of practitioners. Finally,
the confusion and complexity that typifies diagnosis in chronic
pain may justify the selective use of diagnostic blocks that
make anatomic and physiologic sense, even if their validity is
incompletely proved.. 0.
169. Honore, P.; Buritova, J.; Besson, J. M. The effects of morphine on
carrageenin-induced spinal c-Fos expression are completely
blocked by beta-funaltrexamine, a selective mu-opioid
receptor antagonist. Brain-Res. 1996 Sep 2; 732(1-2): 242-6;
ISSN: 0006-8993.
NETHERLANDS. We have demonstrated that pre-administered
morphine (3 mg/kg, i.v.) decreased spinal c-Fos expression
induced 2 h after intraplantar carrageenin (55 +/- 5%
reduction, P < 0.0001). These effects were completely blocked
by pre-administered beta-funaltrexamine (10 mg/kg, i.v., 24 h
prior to stimulation) a selective long-lasting mu-opioid
receptor antagonist. In conclusion, these results clearly
demonstrate that the effects of morphine on noxiously-evoked
spinal c-Fos expression are essentially mediated via mu-
opioid receptors.. 0; 0; 0; 16590-41-3; 57-27-2; 72782-05-9;
9000-07-1.
170. Honore, P.; Buritova, J.; Besson, J. M. The effects of morphine on
carrageenin-induced spinal c-Fos expression are completely
blocked by beta-funaltrexamine, a selective mu-opioid
receptor antagonist. Brain-Res. 1996 Sep 2; 732(1-2): 242-6;
ISSN: 0006-8993.
NETHERLANDS. We have demonstrated that pre-administered
morphine (3 mg/kg, i.v.) decreased spinal c-Fos expression
induced 2 h after intraplantar carrageenin (55 +/- 5%
reduction, P < 0.0001). These effects were completely blocked
by pre-administered beta-funaltrexamine (10 mg/kg, i.v., 24 h
prior to stimulation) a selective long-lasting mu-opioid
receptor antagonist. In conclusion, these results clearly
demonstrate that the effects of morphine on noxiously-evoked
spinal c-Fos expression are essentially mediated via mu-
opioid receptors.. 0; 0; 0; 16590-41-3; 57-27-2; 72782-05-9;
9000-07-1.
171. Horner, P. J.; Popovich, P. G.; Mullin, B. B.; Stokes, B. T. A
quantitative spatial analysis of the blood-spinal cord barrier.
II. Permeability after intraspinal fetal transplantation. Exp-
Neurol. 1996 Dec; 142(2): 226-43; ISSN: 0014-4886.
UNITED-STATES. In previous experiments we utilized
quantitative autoradiography to temporally describe vascular
permeability of a radiolabeled vascular tracer following spinal
contusion injury in the rat. In the present report we compare
these findings with permeability assessments following fetal
grafting in the contused rat spinal cord. At 10 days postinjury,
Embryonic Day 14 spinal tissue was grafted into the lesioned
spinal cord of Sprague-Dawley rats. At 7, 14, and 28 days
postgrafting the alpha-aminoisobutyric acid (AIB) technique
was used to assess blood-to-tissue transfer rates in graft and
host tissue over several segments of the injured spinal cord.
Regional changes in permeability were assessed using four
distinct image analysis techniques. Using these methods, we
have previously shown that contusion injury alone results in a
chronic relapse in vascular permeability. The present data
indicate that fetal transplants at 7 days postgrafting have AIB
transfer rates that are significantly above uninjured control
levels and are similar in magnitude to neighboring host spinal
tissue. In addition, permeability in 14- and 28-day intraspinal
grafts decreased relative to that of the 7-day transplant
group, but remained significantly elevated at and rostral to
the injury epicenter. Alternately, graft and host tissue in
regions caudal to the injury epicenter (e.g., T10--L2) acquired
a functional barrier to AIB as early as 14 days
posttransplantation. These experiments suggest that graft
development occurs in a different manner or at a different
rate in segments of the injured spinal cord rostral and caudal
to the injury site. Additionally, it appears that vascular
permeability of the injured spinal cord can be influenced by
the process of intraspinal transplantation.. 0; 62-57-7.
172. Horner, P. J.; Popovich, P. G.; Mullin, B. B.; Stokes, B. T. A
quantitative spatial analysis of the blood-spinal cord barrier.
II. Permeability after intraspinal fetal transplantation. Exp-
Neurol. 1996 Dec; 142(2): 226-43; ISSN: 0014-4886.
UNITED-STATES. In previous experiments we utilized
quantitative autoradiography to temporally describe vascular
permeability of a radiolabeled vascular tracer following spinal
contusion injury in the rat. In the present report we compare
these findings with permeability assessments following fetal
grafting in the contused rat spinal cord. At 10 days postinjury,
Embryonic Day 14 spinal tissue was grafted into the lesioned
spinal cord of Sprague-Dawley rats. At 7, 14, and 28 days
postgrafting the alpha-aminoisobutyric acid (AIB) technique
was used to assess blood-to-tissue transfer rates in graft and
host tissue over several segments of the injured spinal cord.
Regional changes in permeability were assessed using four
distinct image analysis techniques. Using these methods, we
have previously shown that contusion injury alone results in a
chronic relapse in vascular permeability. The present data
indicate that fetal transplants at 7 days postgrafting have AIB
transfer rates that are significantly above uninjured control
levels and are similar in magnitude to neighboring host spinal
tissue. In addition, permeability in 14- and 28-day intraspinal
grafts decreased relative to that of the 7-day transplant
group, but remained significantly elevated at and rostral to
the injury epicenter. Alternately, graft and host tissue in
regions caudal to the injury epicenter (e.g., T10--L2) acquired
a functional barrier to AIB as early as 14 days
posttransplantation. These experiments suggest that graft
development occurs in a different manner or at a different
rate in segments of the injured spinal cord rostral and caudal
to the injury site. Additionally, it appears that vascular
permeability of the injured spinal cord can be influenced by
the process of intraspinal transplantation.. 0; 62-57-7.
173. Houenou, L. J.; Oppenheim, R. W.; Li, L.; Lo, A. C.; Prevette, D.
Regulation of spinal motoneuron survival by GDNF during
development and following injury. Cell-Tissue-Res. 1996 Nov;
286(2): 219-23; ISSN: 0302-766X.
GERMANY. During normal development of many vertebrate
species, substantial numbers of neurons in the central and
peripheral nervous system undergo naturally occurring (or
programmed) cell death. For example, approximately 50% of
spinal motoneurons degenerate and die at a time when these
cells are establishing synaptic connections with their target
muscles in the chick, mouse, rat, and human. It is generally
thought that the survival of developing motoneurons depends
on access to trophic molecules. Motoneurons that survive the
period of programmed cell death may also die following injury
in the developing or adult animal. Increasing evidence suggests
that glial-cell-line-derived neurotrophic factor (GDNF) plays a
physiological and/or pharmacological role in the survival of
various neuronal cell types, including motoneurons. In this
paper, we review the survival and growth-promoting effects
of GDNF on spinal motoneurons during the period of
programmed cell death and following injury.. 0; 0; 0.
174. Houenou, L. J.; Oppenheim, R. W.; Li, L.; Lo, A. C.; Prevette, D.
Regulation of spinal motoneuron survival by GDNF during
development and following injury. Cell-Tissue-Res. 1996 Nov;
286(2): 219-23; ISSN: 0302-766X.
GERMANY. During normal development of many vertebrate
species, substantial numbers of neurons in the central and
peripheral nervous system undergo naturally occurring (or
programmed) cell death. For example, approximately 50% of
spinal motoneurons degenerate and die at a time when these
cells are establishing synaptic connections with their target
muscles in the chick, mouse, rat, and human. It is generally
thought that the survival of developing motoneurons depends
on access to trophic molecules. Motoneurons that survive the
period of programmed cell death may also die following injury
in the developing or adult animal. Increasing evidence suggests
that glial-cell-line-derived neurotrophic factor (GDNF) plays a
physiological and/or pharmacological role in the survival of
various neuronal cell types, including motoneurons. In this
paper, we review the survival and growth-promoting effects
of GDNF on spinal motoneurons during the period of
programmed cell death and following injury.. 0; 0; 0.
175. Icten, N.; Memedova, E.; Sullu, Y. Vertebral level of the ending of
the spinal cord and its relationship to the length of the
vertebral column in northern Turkish neonates. Surg-Radiol-
Anat. 1995; 17(4): 315-8; ISSN: 0930-1038.
GERMANY. Racial and sex differences in the level of ending of
the spinal cord of the adult have been reported. It is lower in
Africans and in females. Since such differences may affect
even fetuses and newborns we aimed to study in Northern
Turkish neonates. The study was made on 40 full-term
newborn still-births (23 male, 17 female). In all cases, the
length of the vertebral column, the length of the spinal cord
and the body weight were measured and the vertebral level of
ending of the spinal cord was noted. It was found that the
termination of the spinal cord varied from the first lumbar to
the second sacral vertebra, with a mean level between L2 and
L3. In female neonates, it was observed that the spinal cord
ended at a slightly lower level (0.2 vertebra) than in males.
Our findings approximately agreed with those of Barson [2]
who studied neonates in England and of Jit and Charnalia [5] in
North India. However, we found that the spinal cord ended one
and half vertebrae lower in Northern Turkish neonates than in
South African and South Indian subjects. The correlations
between body-weight and length of the spinal cord, weight and
length of the vertebral column, length of the spinal cord and
length of vertebral column, length of the vertebral column and
level of ending of the cord were statistically highly
significant for males, females and both sexes together (p <
0.001). The longer the vertebral column, the higher the
termination of the spinal cord.
176. Icten, N.; Memedova, E.; Sullu, Y. Vertebral level of the ending of
the spinal cord and its relationship to the length of the
vertebral column in northern Turkish neonates. Surg-Radiol-
Anat. 1995; 17(4): 315-8; ISSN: 0930-1038.
GERMANY. Racial and sex differences in the level of ending of
the spinal cord of the adult have been reported. It is lower in
Africans and in females. Since such differences may affect
even fetuses and newborns we aimed to study in Northern
Turkish neonates. The study was made on 40 full-term
newborn still-births (23 male, 17 female). In all cases, the
length of the vertebral column, the length of the spinal cord
and the body weight were measured and the vertebral level of
ending of the spinal cord was noted. It was found that the
termination of the spinal cord varied from the first lumbar to
the second sacral vertebra, with a mean level between L2 and
L3. In female neonates, it was observed that the spinal cord
ended at a slightly lower level (0.2 vertebra) than in males.
Our findings approximately agreed with those of Barson [2]
who studied neonates in England and of Jit and Charnalia [5] in
North India. However, we found that the spinal cord ended one
and half vertebrae lower in Northern Turkish neonates than in
South African and South Indian subjects. The correlations
between body-weight and length of the spinal cord, weight and
length of the vertebral column, length of the spinal cord and
length of vertebral column, length of the vertebral column and
level of ending of the cord were statistically highly
significant for males, females and both sexes together (p <
0.001). The longer the vertebral column, the higher the
termination of the spinal cord.
177. Ikemoto, A.; Hirano, A. Immunohistochemical studies on clustered
pericapillary bodies in the spinal cord of post-poliomyelitis
patients. Acta-Neuropathol-Berl. 1996 Aug; 92(2): 164-9;
ISSN: 0001-6322.
GERMANY. This report concerns the study of clustered
pericapillary bodies in the spinal cords of four post-
poliomyelitis patients. All four had stable neurological
deficits without new neurological symptoms after the initial
poliomyelitis infection. Spinal cords from seven individuals
who died of non-neurological disorders served as controls.
Lumbar spinal segments were examined by using conventional
staining procedures and immunohistochemical techniques. The
histological features of the pericapillary structures were
similar to those of the previously described pericapillary
rosettes. The number of pericapillary bodies was strikingly
greater in one post-poliomyelitis patient (a man who died at
age 48) than in the other three. The great majority of the
pericapillary structures were within the areas of the
poliomyelitis lesions. A small number of the abnormal
structures were detected in the lumbar spinal cord of three
control individuals. The clustered pericapillary bodies were
immunostained by antibodies to phosphorylated neurofilament,
synaptophysin, and ubiquitin, but not by antibodies to glial
fibrillary acidic protein, tau protein, and paired helical
filaments. These results indicate that the structures may
derive from presynaptic terminals and preterminal axons, and
that their formation may be related, albeit not necessarily in a
specific fashion, to the poliomyelitis disease process.
178. Ikemoto, A.; Hirano, A. Immunohistochemical studies on clustered
pericapillary bodies in the spinal cord of post-poliomyelitis
patients. Acta-Neuropathol-Berl. 1996 Aug; 92(2): 164-9;
ISSN: 0001-6322.
GERMANY. This report concerns the study of clustered
pericapillary bodies in the spinal cords of four post-
poliomyelitis patients. All four had stable neurological
deficits without new neurological symptoms after the initial
poliomyelitis infection. Spinal cords from seven individuals
who died of non-neurological disorders served as controls.
Lumbar spinal segments were examined by using conventional
staining procedures and immunohistochemical techniques. The
histological features of the pericapillary structures were
similar to those of the previously described pericapillary
rosettes. The number of pericapillary bodies was strikingly
greater in one post-poliomyelitis patient (a man who died at
age 48) than in the other three. The great majority of the
pericapillary structures were within the areas of the
poliomyelitis lesions. A small number of the abnormal
structures were detected in the lumbar spinal cord of three
control individuals. The clustered pericapillary bodies were
immunostained by antibodies to phosphorylated neurofilament,
synaptophysin, and ubiquitin, but not by antibodies to glial
fibrillary acidic protein, tau protein, and paired helical
filaments. These results indicate that the structures may
derive from presynaptic terminals and preterminal axons, and
that their formation may be related, albeit not necessarily in a
specific fashion, to the poliomyelitis disease process.
179. Iles, J. F. Evidence for cutaneous and corticospinal modulation of
presynaptic inhibition of Ia afferents from the human lower
limb. J-Physiol-Lond. 1996 Feb 15; 491( Pt 1): 197-207; ISSN:
0022-3751.
ENGLAND. 1. Presynaptic inhibition of soleus muscle Ia
afferent fibres, produced by stimulation of group I afferents in
the common peroneal nerve, was assessed from changes in the
H reflex at long conditioning intervals, in six normal subjects.
2. Stimulation of the ipsilateral sural nerve at the malleolus,
just before stimulation of the common peroneal nerve at the
head of the fibula, decreased the presynaptic inhibition. This
effect was strongest during voluntary plantar flexion and
weaker during dorsiflexion or at rest. 3. Stimulation of other
cutaneous nerve branches serving the dorsum of the ipsilateral
foot, and also the contralateral sural nerve, decreased
presynaptic inhibition. Adequate stimulation of low threshold
cutaneous mechanoreceptors by light brushing of both distal
dorsal and plantar surfaces of the ipsilateral foot decreased
presynaptic inhibition. 4. Stimulation of the ipsilateral plantar
nerves increased presynaptic inhibition, but this action is
attributed to activation of group I afferents from the intrinsic
muscles of the foot. 5. Transcranial magnetic stimulation of
the lower limb area of the contralateral motor cortex
decreased presynaptic inhibition. This effect was strongest
during voluntary plantar flexion and weaker during
dorsiflexion or at rest. 6. The actions of cutaneous and
corticospinal pathways completely occluded each other.
However, when both effects were adjusted to be liminal, a
spatial facilitation between them was observed. 7. It is
concluded that in man, as in the cat, cutaneous and
corticospinal axons converge on interneurones that inhibit the
machinery of presynaptic inhibition of group Ia afferents.
These actions may be responsible for the modulation of
presynaptic inhibition which has been observed to precede and
accompany a wide range of human movements.. 0.
180. Iles, J. F. Evidence for cutaneous and corticospinal modulation of
presynaptic inhibition of Ia afferents from the human lower
limb. J-Physiol-Lond. 1996 Feb 15; 491( Pt 1): 197-207; ISSN:
0022-3751.
ENGLAND. 1. Presynaptic inhibition of soleus muscle Ia
afferent fibres, produced by stimulation of group I afferents in
the common peroneal nerve, was assessed from changes in the
H reflex at long conditioning intervals, in six normal subjects.
2. Stimulation of the ipsilateral sural nerve at the malleolus,
just before stimulation of the common peroneal nerve at the
head of the fibula, decreased the presynaptic inhibition. This
effect was strongest during voluntary plantar flexion and
weaker during dorsiflexion or at rest. 3. Stimulation of other
cutaneous nerve branches serving the dorsum of the ipsilateral
foot, and also the contralateral sural nerve, decreased
presynaptic inhibition. Adequate stimulation of low threshold
cutaneous mechanoreceptors by light brushing of both distal
dorsal and plantar surfaces of the ipsilateral foot decreased
presynaptic inhibition. 4. Stimulation of the ipsilateral plantar
nerves increased presynaptic inhibition, but this action is
attributed to activation of group I afferents from the intrinsic
muscles of the foot. 5. Transcranial magnetic stimulation of
the lower limb area of the contralateral motor cortex
decreased presynaptic inhibition. This effect was strongest
during voluntary plantar flexion and weaker during
dorsiflexion or at rest. 6. The actions of cutaneous and
corticospinal pathways completely occluded each other.
However, when both effects were adjusted to be liminal, a
spatial facilitation between them was observed. 7. It is
concluded that in man, as in the cat, cutaneous and
corticospinal axons converge on interneurones that inhibit the
machinery of presynaptic inhibition of group Ia afferents.
These actions may be responsible for the modulation of
presynaptic inhibition which has been observed to precede and
accompany a wide range of human movements.. 0.
181. Ivanco, T. L.; Pellis, S. M.; Whishaw, I. Q. Skilled forelimb
movements in prey catching and in reaching by rats (Rattus
norvegicus) and opossums (Monodelphis domestica): relations
to anatomical differences in motor systems. Behav-Brain-Res.
1996 Sep; 79(1-2): 163-81; ISSN: 0166-4328.
NETHERLANDS. Traditional anatomical/behavioral
classifications suggest that rats and opossums have simple
motor systems and are impoverished with respect to their
ability to make prehensile movements. Nevertheless, the motor
system in rats and opossums represent extremes in relative
size and complexity suggesting that a behavioral analysis of
the movement competencies of these species will provide
insights into the significance of such anatomical differences.
This paper examines the movements that the two species use
in catching crickets and in reaching for food items. Both
species could use a single limb to reach out and grasp prey
during prey catching and both could use a single limb to take
food from a shelf. Both species could transport the food to the
mouth by using a single paw. The food handling behavior of the
rats was more complex than that of the opossums, however.
They used a variety of prey catching movements and
extensively manipulated the prey to remove the legs and wings
before eating only the head and body. Additionally the rats
made rotatory limb movements of aiming, pronation, and
supination, when reaching. For both cricket catching and
reaching, they used their digits more than did the opossums.
The suggestion also emerged from the results that the
movements of the opossums were more fixed and species-
typical whereas those of the rats were more plastic and
individualistic. Thus, the skilled movements of both species
are more complex than is generally recognized and the greater
complexity of the rat movements parallels their more complex
motor system. These results are discussed in relation to
anatomical differences in the motor system and, specifically,
to differences in the terminal fields of the pyramidal tract. It
is concluded that the motor abilities of nonprimate mammals
have been vastly underrated.
182. Ivanco, T. L.; Pellis, S. M.; Whishaw, I. Q. Skilled forelimb
movements in prey catching and in reaching by rats (Rattus
norvegicus) and opossums (Monodelphis domestica): relations
to anatomical differences in motor systems. Behav-Brain-Res.
1996 Sep; 79(1-2): 163-81; ISSN: 0166-4328.
NETHERLANDS. Traditional anatomical/behavioral
classifications suggest that rats and opossums have simple
motor systems and are impoverished with respect to their
ability to make prehensile movements. Nevertheless, the motor
system in rats and opossums represent extremes in relative
size and complexity suggesting that a behavioral analysis of
the movement competencies of these species will provide
insights into the significance of such anatomical differences.
This paper examines the movements that the two species use
in catching crickets and in reaching for food items. Both
species could use a single limb to reach out and grasp prey
during prey catching and both could use a single limb to take
food from a shelf. Both species could transport the food to the
mouth by using a single paw. The food handling behavior of the
rats was more complex than that of the opossums, however.
They used a variety of prey catching movements and
extensively manipulated the prey to remove the legs and wings
before eating only the head and body. Additionally the rats
made rotatory limb movements of aiming, pronation, and
supination, when reaching. For both cricket catching and
reaching, they used their digits more than did the opossums.
The suggestion also emerged from the results that the
movements of the opossums were more fixed and species-
typical whereas those of the rats were more plastic and
individualistic. Thus, the skilled movements of both species
are more complex than is generally recognized and the greater
complexity of the rat movements parallels their more complex
motor system. These results are discussed in relation to
anatomical differences in the motor system and, specifically,
to differences in the terminal fields of the pyramidal tract. It
is concluded that the motor abilities of nonprimate mammals
have been vastly underrated.
183. Iwamoto, Y.; Perlmutter, S. I.; Baker, J. F.; Peterson, B. W. Spatial
coordination by descending vestibular signals. 2. Response
properties of medial and lateral vestibulospinal tract neurons
in alert and decerebrate cats. Exp-Brain-Res. 1996 Feb; 108(1):
85-100; ISSN: 0014-4819.
GERMANY. Spatial response properties of medial (MVST) and
lateral (LVST) vestibulospinal tract neurons were studied in
alert and decerebrate cats during sinusoidal angular rotations
of the whole body in the horizontal and many vertical planes.
Of 220 vestibulospinal neurons with activity modulated during
0.5-Hz sinusoidal rotations, 200 neurons exhibited response
gains that varied as a cosine function of stimulus orientation
and phases that were near head velocity for rotation planes far
from the minimum response plane. A maximum activation
direction vector (MAD), which represents the axis and
direction of rotation that maximally excites the neuron, was
calculated for these neurons. Spatial properties of secondary
MVST neurons in alert and decerebrate animals were similar.
The responses of 88 of 134 neurons (66%) could be accounted
for by input from one semicircular canal pair. Of these, 84 had
responses consistent with excitation from the ipsilateral
canal of the pair (13 horizontal, 27 anterior, 44 posterior) and
4 with excitation from the contralateral horizontal canal. The
responses of the remaining 46 (34%) neurons suggested
convergent inputs. The activity of 38 of these was
significantly modulated by both horizontal and vertical
rotations. Twelve neurons (9%) had responses that were
consistent with input from both vertical canal pairs, including
9 cells with MADs near the roll axis. Thirty-two secondary
MVST neurons (24%) had type II yaw and/or roll responses. The
spatial response properties of 18 secondary LVST neurons, all
studied in decerebrate animals, were different from those of
secondary MVST neurons. Sixteen neurons (89%) had type II
yaw and/or roll responses, and 12 (67%) appeared to receive
convergent canal pair input. Convergent input was more
common on higher-order vestibulospinal neurons than on
secondary neurons. These results suggest that MVST and LVST
neurons and previously reported vestibulo-ocular neurons
transmit functionally different signals. LVST neurons,
particularly those with MADs close to the roll axis, may be
involved in the vestibular-limb reflex. The combination of
vertical and ipsilateral horizontal canal input on many
secondary MVST neurons suggests a contribution to the
vestibulocollic reflex. However, in contrast to most neck
muscles, very few neurons had maximum vertical responses
near pitch.
184. Iwamoto, Y.; Perlmutter, S. I.; Baker, J. F.; Peterson, B. W. Spatial
coordination by descending vestibular signals. 2. Response
properties of medial and lateral vestibulospinal tract neurons
in alert and decerebrate cats. Exp-Brain-Res. 1996 Feb; 108(1):
85-100; ISSN: 0014-4819.
GERMANY. Spatial response properties of medial (MVST) and
lateral (LVST) vestibulospinal tract neurons were studied in
alert and decerebrate cats during sinusoidal angular rotations
of the whole body in the horizontal and many vertical planes.
Of 220 vestibulospinal neurons with activity modulated during
0.5-Hz sinusoidal rotations, 200 neurons exhibited response
gains that varied as a cosine function of stimulus orientation
and phases that were near head velocity for rotation planes far
from the minimum response plane. A maximum activation
direction vector (MAD), which represents the axis and
direction of rotation that maximally excites the neuron, was
calculated for these neurons. Spatial properties of secondary
MVST neurons in alert and decerebrate animals were similar.
The responses of 88 of 134 neurons (66%) could be accounted
for by input from one semicircular canal pair. Of these, 84 had
responses consistent with excitation from the ipsilateral
canal of the pair (13 horizontal, 27 anterior, 44 posterior) and
4 with excitation from the contralateral horizontal canal. The
responses of the remaining 46 (34%) neurons suggested
convergent inputs. The activity of 38 of these was
significantly modulated by both horizontal and vertical
rotations. Twelve neurons (9%) had responses that were
consistent with input from both vertical canal pairs, including
9 cells with MADs near the roll axis. Thirty-two secondary
MVST neurons (24%) had type II yaw and/or roll responses. The
spatial response properties of 18 secondary LVST neurons, all
studied in decerebrate animals, were different from those of
secondary MVST neurons. Sixteen neurons (89%) had type II
yaw and/or roll responses, and 12 (67%) appeared to receive
convergent canal pair input. Convergent input was more
common on higher-order vestibulospinal neurons than on
secondary neurons. These results suggest that MVST and LVST
neurons and previously reported vestibulo-ocular neurons
transmit functionally different signals. LVST neurons,
particularly those with MADs close to the roll axis, may be
involved in the vestibular-limb reflex. The combination of
vertical and ipsilateral horizontal canal input on many
secondary MVST neurons suggests a contribution to the
vestibulocollic reflex. However, in contrast to most neck
muscles, very few neurons had maximum vertical responses
near pitch.
185. Jacquin, T. D.; Borday, V.; Schneider Maunoury, S.; Topilko, P.;
Ghilini, G.; Kato, F.; Charnay, P.; Champagnat, J. Reorganization
of pontine rhythmogenic neuronal networks in Krox-20
knockout mice. Neuron. 1996 Oct; 17(4): 747-58; ISSN: 0896-
6273.
UNITED-STATES. We have shown previously that the
inactivation of the zinc finger gene Krox-20 affects hindbrain
segmentation, resulting in the elimination of rhombomeres 3
and 5. We demonstrate here that Krox-20 homozygous mutant
mice exhibit abnormally slow respiratory and jaw opening
rhythms, indicating that a modification of hindbrain
segmentation influences the function of neuronal networks
after birth. Central neuronal networks that control respiratory
frequency are made predominantly depressant by the
elimination of a previously undescribed rhythm-promoting
system. Recordings of rhythmic activity from the isolated
hindbrain following progressive tissue transections indicate
that the reorganization takes place in the caudal pontine
reticular formation. The newborn (PO) Krox-20-/- mice, in
which apneas are ten times longer than in wild-type animals,
may be a valuable model for the study of life-threatening
apneas during early infancy.. 0; 0; 0; 465-65-6.
186. Jacquin, T. D.; Borday, V.; Schneider Maunoury, S.; Topilko, P.;
Ghilini, G.; Kato, F.; Charnay, P.; Champagnat, J. Reorganization
of pontine rhythmogenic neuronal networks in Krox-20
knockout mice. Neuron. 1996 Oct; 17(4): 747-58; ISSN: 0896-
6273.
UNITED-STATES. We have shown previously that the
inactivation of the zinc finger gene Krox-20 affects hindbrain
segmentation, resulting in the elimination of rhombomeres 3
and 5. We demonstrate here that Krox-20 homozygous mutant
mice exhibit abnormally slow respiratory and jaw opening
rhythms, indicating that a modification of hindbrain
segmentation influences the function of neuronal networks
after birth. Central neuronal networks that control respiratory
frequency are made predominantly depressant by the
elimination of a previously undescribed rhythm-promoting
system. Recordings of rhythmic activity from the isolated
hindbrain following progressive tissue transections indicate
that the reorganization takes place in the caudal pontine
reticular formation. The newborn (PO) Krox-20-/- mice, in
which apneas are ten times longer than in wild-type animals,
may be a valuable model for the study of life-threatening
apneas during early infancy.. 0; 0; 0; 465-65-6.
187. Jennum, P.; Winkel, H.; Fuglsang Frederiksen, A. Paired
transcranial magnetic stimulations and motor evoked
potentials. Electromyogr-Clin-Neurophysiol. 1996 Sep; 36(6):
341-8; ISSN: 0301-150X.
BELGIUM. We studied the effect of varying interstimulus
intervals (ISI) on the motor evoked potentials (MEP) using
paired transcranial magnetic stimulation (PTMS) during
relaxation and voluntary contraction of the abductor pollicis
brevis. At ISI > or = 10 ms two independent MEPs could be
evoked. At ISIs between 12-30 ms the amplitudes of the MEPs
evoked by the second (test) stimuli had larger amplitude and
shorter latencies than the MEPs evoked by the first
(conditioning) stimuli. At an ISI of 50 ms the second MEP were
similar to the first, between 75 and 100 ms the second MEPs
were inhibited and at ISI of 200 and 400 ms the second MEPs
showed almost similar amplitudes and latencies compared to
the first. During voluntary contraction, the amplitudes of the
first MEPs was higher compared to relaxed responses. The
amplitudes of the second MEPs showed a similar pattern as the
relaxed responses, but with a relatively smaller increase
between 12-30 ms (p < 0.01), and less inhibition at 75 and 100
ms (p < 0.01). The study shows that conditioning stimuli 12-30
ms before the test stimulus facilitates the second MEP, and an
ISI between 75-100 ms inhibit the second MEP. Voluntary
contraction exerts a facilatory effect and reduce inhibition in
the corticospinal neurons. These findings may reflects the
changes in excitability and inhibition in the cortico-spinal
neurons.
188. Jennum, P.; Winkel, H.; Fuglsang Frederiksen, A. Paired
transcranial magnetic stimulations and motor evoked
potentials. Electromyogr-Clin-Neurophysiol. 1996 Sep; 36(6):
341-8; ISSN: 0301-150X.
BELGIUM. We studied the effect of varying interstimulus
intervals (ISI) on the motor evoked potentials (MEP) using
paired transcranial magnetic stimulation (PTMS) during
relaxation and voluntary contraction of the abductor pollicis
brevis. At ISI > or = 10 ms two independent MEPs could be
evoked. At ISIs between 12-30 ms the amplitudes of the MEPs
evoked by the second (test) stimuli had larger amplitude and
shorter latencies than the MEPs evoked by the first
(conditioning) stimuli. At an ISI of 50 ms the second MEP were
similar to the first, between 75 and 100 ms the second MEPs
were inhibited and at ISI of 200 and 400 ms the second MEPs
showed almost similar amplitudes and latencies compared to
the first. During voluntary contraction, the amplitudes of the
first MEPs was higher compared to relaxed responses. The
amplitudes of the second MEPs showed a similar pattern as the
relaxed responses, but with a relatively smaller increase
between 12-30 ms (p < 0.01), and less inhibition at 75 and 100
ms (p < 0.01). The study shows that conditioning stimuli 12-30
ms before the test stimulus facilitates the second MEP, and an
ISI between 75-100 ms inhibit the second MEP. Voluntary
contraction exerts a facilatory effect and reduce inhibition in
the corticospinal neurons. These findings may reflects the
changes in excitability and inhibition in the cortico-spinal
neurons.
189. Ji, Z.; Hawkes, R. Partial ablation of the neonatal external
granular layer disrupts mossy fiber topography in the adult rat
cerebellum. J-Comp-Neurol. 1996 Aug 5; 371(4): 578-88; ISSN:
0021-9967.
UNITED-STATES. The spinocerebellar projection in the rat is
compartmentalized in an array of parasagittal bands of mossy
fiber terminals. These bands align reproducibly with bands of
Purkinje cells that differentially express zebrin II. To
investigate whether this alignment is obligatory, Purkinje cell
and mossy fiber compartmentation has been compared in the
rat cerebellum where the cytoarchitecture was contorted by
neonatal administration of methylazoxymethanol.
Methylazoxymethanol ablates many granule cell precursors,
leaving a much reduced external granular layer, and adult rats
that received a single methylazoxymethanol injection at birth
showed varying degrees of abnormal cerebellar foliation.
Zebrin II immunocytochemistry nevertheless revealed no
fundamental abnormality in the Purkinje cell compartments.
However, despite the normal Purkinje cell compartmentation
being retained, the spinocerebellar mossy fiber-Purkinje cell
topography is disrupted by methylazoxymethanol treatment.
The normal precise array of parasagittal mossy fiber terminal
fields becomes blurred across the lobule, and the normal clear
banding is difficult to follow. These data suggest that, despite
the early topography being dependent on the Purkinje cells, the
granule cell-mossy fiber interactions also regulate the
topography of the spinocerebellar projection.. 0; 0; 590-96-5;
592-62-1.
190. Ji, Z.; Hawkes, R. Partial ablation of the neonatal external
granular layer disrupts mossy fiber topography in the adult rat
cerebellum. J-Comp-Neurol. 1996 Aug 5; 371(4): 578-88; ISSN:
0021-9967.
UNITED-STATES. The spinocerebellar projection in the rat is
compartmentalized in an array of parasagittal bands of mossy
fiber terminals. These bands align reproducibly with bands of
Purkinje cells that differentially express zebrin II. To
investigate whether this alignment is obligatory, Purkinje cell
and mossy fiber compartmentation has been compared in the
rat cerebellum where the cytoarchitecture was contorted by
neonatal administration of methylazoxymethanol.
Methylazoxymethanol ablates many granule cell precursors,
leaving a much reduced external granular layer, and adult rats
that received a single methylazoxymethanol injection at birth
showed varying degrees of abnormal cerebellar foliation.
Zebrin II immunocytochemistry nevertheless revealed no
fundamental abnormality in the Purkinje cell compartments.
However, despite the normal Purkinje cell compartmentation
being retained, the spinocerebellar mossy fiber-Purkinje cell
topography is disrupted by methylazoxymethanol treatment.
The normal precise array of parasagittal mossy fiber terminal
fields becomes blurred across the lobule, and the normal clear
banding is difficult to follow. These data suggest that, despite
the early topography being dependent on the Purkinje cells, the
granule cell-mossy fiber interactions also regulate the
topography of the spinocerebellar projection.. 0; 0; 590-96-5;
592-62-1.
191. Johnson, B. M.; Komisaruk, B. R. Antinociceptive action of
vaginocervical stimulation in rat spinal cord: 2-DG analysis.
Physiol-Behav. 1996 Sep; 60(3): 979-83; ISSN: 0031-9384.
UNITED-STATES. Using [14C] 2-deoxyglucose (2-DG)
autoradiography with computerized densitometric analysis,
unilateral foot pinch was found to significantly increase the
relative optical density in laminae I and II of the ipsilateral,
compared to the contralateral, spinal cord at lumbar 5 (L5).
However, during vaginocervical mechanostimulation applied
concurrently with the unilateral foot pinch, no comparable
difference was observed. No response to foot pinch was
observed in other laminae of the spinal cord at L5, and no
effects comparable to the above were observed at L3. These
findings indicate that vaginocervical mechanostimulation
suppresses neural responses to noxious foot pinch stimulation
selectively at the laminae I and II level of the spinal cord at
L5, but not at L3.. 154-17-6.
192. Johnson, B. M.; Komisaruk, B. R. Antinociceptive action of
vaginocervical stimulation in rat spinal cord: 2-DG analysis.
Physiol-Behav. 1996 Sep; 60(3): 979-83; ISSN: 0031-9384.
UNITED-STATES. Using [14C] 2-deoxyglucose (2-DG)
autoradiography with computerized densitometric analysis,
unilateral foot pinch was found to significantly increase the
relative optical density in laminae I and II of the ipsilateral,
compared to the contralateral, spinal cord at lumbar 5 (L5).
However, during vaginocervical mechanostimulation applied
concurrently with the unilateral foot pinch, no comparable
difference was observed. No response to foot pinch was
observed in other laminae of the spinal cord at L5, and no
effects comparable to the above were observed at L3. These
findings indicate that vaginocervical mechanostimulation
suppresses neural responses to noxious foot pinch stimulation
selectively at the laminae I and II level of the spinal cord at
L5, but not at L3.. 154-17-6.
193. Jones, S. J.; Harrison, R.; Koh, K. F.; Mendoza, N.; Crockard, H. A.
Motor evoked potential monitoring during spinal surgery:
responses of distal limb muscles to transcranial cortical
stimulation with pulse trains. Electroencephalogr-Clin-
Neurophysiol. 1996 Sep; 100(5): 375-83; ISSN: 0013-4694.
IRELAND. During spinal surgery, motor evoked potentials
(MEPs) were recorded from distal upper and lower limb
muscles following multipulse transcranial electrical
stimulation of the cortex. Twenty-two patients, 9 of them
myelopathic, were anaesthetised with propofol +/- nitrous
oxide. Using trains of 3-6 pulses separated by 2 ms, consistent
responses generally measuring more than 100 microV were
obtained from every patient except one, and persisted with
nitrous oxide concentrations as high as 74%. Responses could
usually be elicited from 3 or more limbs simultaneously,
although the location of the stimulating anode was sometimes
critical. The lower limb responses of one patient disappeared
transiently during excision of an intramedullary tumour; his
leg weakness was increased for a few days after surgery.
Three other patients experienced increased weakness or
spasticity, two without concomitant MEP changes and one with
no recordable responses. Although other methods may be
preferable in some circumstances, we believe this represents
an advance over previously reported non-invasive techniques
for peroperative MEP monitoring, and may be particularly
useful for monitoring patients with myelopathy in the thoracic
region.
194. Jones, S. J.; Harrison, R.; Koh, K. F.; Mendoza, N.; Crockard, H. A.
Motor evoked potential monitoring during spinal surgery:
responses of distal limb muscles to transcranial cortical
stimulation with pulse trains. Electroencephalogr-Clin-
Neurophysiol. 1996 Sep; 100(5): 375-83; ISSN: 0013-4694.
IRELAND. During spinal surgery, motor evoked potentials
(MEPs) were recorded from distal upper and lower limb
muscles following multipulse transcranial electrical
stimulation of the cortex. Twenty-two patients, 9 of them
myelopathic, were anaesthetised with propofol +/- nitrous
oxide. Using trains of 3-6 pulses separated by 2 ms, consistent
responses generally measuring more than 100 microV were
obtained from every patient except one, and persisted with
nitrous oxide concentrations as high as 74%. Responses could
usually be elicited from 3 or more limbs simultaneously,
although the location of the stimulating anode was sometimes
critical. The lower limb responses of one patient disappeared
transiently during excision of an intramedullary tumour; his
leg weakness was increased for a few days after surgery.
Three other patients experienced increased weakness or
spasticity, two without concomitant MEP changes and one with
no recordable responses. Although other methods may be
preferable in some circumstances, we believe this represents
an advance over previously reported non-invasive techniques
for peroperative MEP monitoring, and may be particularly
useful for monitoring patients with myelopathy in the thoracic
region.
195. Jorntell, H.; Garwicz, M.; Ekerot, C. F. Relation between cutaneous
receptive fields and muscle afferent input to climbing fibres
projecting to the cerebellar C3 zone in the cat. Eur-J-Neurosci.
1996 Aug; 8(8): 1769-79; ISSN: 0953-816X.
ENGLAND. Inferior olivary cells projecting as climbing fibres
to the forelimb area of the cerebellar C3 zone were
investigated with respect to their cutaneous and muscle
afferent input in barbiturate-anaesthetized cats. Climbing
fibre responses were recorded from single cerebellar cortical
Purkinje cells on natural stimulation of the skin and on
electrical stimulation of nerves to m. biceps brachii, m.
triceps brachii and to nine muscles acting as dorsal or palmar
flexors of the paw (and, in some cases, the digits). The
analysis was focused on the functional organization of
convergence between cutaneous and muscle afferents onto
single olivary neurons. Cutaneous receptive fields on the
dorsal side of the paw and on the digits were generally
associated with moderate to strong input from dorsal flexors,
but little or no input from palmar flexors or proximal muscles.
Receptive fields on the ventral side of the paw and forearm
were associated with relatively strong input from biceps and
palmar flexors. Climbing fibres with cutaneous receptive
fields extending on the ulnar side of the paw and forearm
usually received strong input from the triceps and moderate to
strong input from dorsal flexors, whereas input from the
palmar flexors was weak or lacking. In conclusion, the results
indicate that the cutaneous receptive fields in many cases are
associated with input from muscles the action of which would
tend to move the receptive field towards a stimulus applied to
the skin.
196. Jorntell, H.; Garwicz, M.; Ekerot, C. F. Relation between cutaneous
receptive fields and muscle afferent input to climbing fibres
projecting to the cerebellar C3 zone in the cat. Eur-J-Neurosci.
1996 Aug; 8(8): 1769-79; ISSN: 0953-816X.
ENGLAND. Inferior olivary cells projecting as climbing fibres
to the forelimb area of the cerebellar C3 zone were
investigated with respect to their cutaneous and muscle
afferent input in barbiturate-anaesthetized cats. Climbing
fibre responses were recorded from single cerebellar cortical
Purkinje cells on natural stimulation of the skin and on
electrical stimulation of nerves to m. biceps brachii, m.
triceps brachii and to nine muscles acting as dorsal or palmar
flexors of the paw (and, in some cases, the digits). The
analysis was focused on the functional organization of
convergence between cutaneous and muscle afferents onto
single olivary neurons. Cutaneous receptive fields on the
dorsal side of the paw and on the digits were generally
associated with moderate to strong input from dorsal flexors,
but little or no input from palmar flexors or proximal muscles.
Receptive fields on the ventral side of the paw and forearm
were associated with relatively strong input from biceps and
palmar flexors. Climbing fibres with cutaneous receptive
fields extending on the ulnar side of the paw and forearm
usually received strong input from the triceps and moderate to
strong input from dorsal flexors, whereas input from the
palmar flexors was weak or lacking. In conclusion, the results
indicate that the cutaneous receptive fields in many cases are
associated with input from muscles the action of which would
tend to move the receptive field towards a stimulus applied to
the skin.
197. Joseph, S. J.; Ford, M. D.; Barth, C.; Portbury, S.; Bartlett, P. F.;
Nurcombe, V.; Greferath, U. A proteoglycan that activates
fibroblast growth factors during early neuronal development is
a perlecan variant. Development. 1996 Nov; 122(11): 3443-52;
ISSN: 0950-1991.
ENGLAND. Cells in the early embryonic vertebrate nervous
system are dependent on members of the fibroblast growth
factor (FGF) family for their proliferation and subsequent
differentiation. These growth factors will only bind to their
specific high affinity cell surface receptors after formation
of a ternary complex with the glycosaminoglycan heparan
sulfate. Such specific heparan sulfates are secreted as
proteoglycans from neural precursor cells and localise to their
surfaces. One such proteoglycan, HSPG-PRM (Perlecan-related
molecule), was isolated through its ability to potentiate
neural cell responses to either FGF-1 or FGF-2. In this study,
we have verified the relative molecular mass of the core
protein of PRM as 45,000 and obtained partial amino acid
sequence from it. The sequences bore significant homology to
native perlecan. A probe generated by reverse transcriptase
polymerase chain reaction using oligonucleotides designed
from the protein sequence used on northern blots of RNA from
a neuroepithelial cell line detected perlecan at 12.6 kilobases,
as well as novel transcripts at 6.5 and 3.5 kilobases. The
latter species appears by virtue of its size and abundance to
be the novel PRM transcript. PRM appears to be encoded by the
same gene as perlecan, as genomic Southern blotting only
detected a single gene. Polyclonal antibodies raised against
the PRM molecule detected a single proteoglycan species at
290x10(3) with a core protein of 45x10(3). Polyclonal anti-
perlecan antibodies cross-reacted with PRM confirming their
relatedness, although immunohistochemical studies revealed a
differential staining pattern for PRM as compared to perlecan
within the developing nervous system. The PRM molecule was
shown to be localised to several different tissues of the
developing embryo, indicating that it plays a broad role. We
conclude that PRM is a variant of perlecan that is
differentially glycosylated in a manner that confers highly
specific functions at critical stages of neural development and
tissue growth.. 0; 0; 0; 143972-95-6; 62031-54-3; 9050-30-
0.
198. Joseph, S. J.; Ford, M. D.; Barth, C.; Portbury, S.; Bartlett, P. F.;
Nurcombe, V.; Greferath, U. A proteoglycan that activates
fibroblast growth factors during early neuronal development is
a perlecan variant. Development. 1996 Nov; 122(11): 3443-52;
ISSN: 0950-1991.
ENGLAND. Cells in the early embryonic vertebrate nervous
system are dependent on members of the fibroblast growth
factor (FGF) family for their proliferation and subsequent
differentiation. These growth factors will only bind to their
specific high affinity cell surface receptors after formation
of a ternary complex with the glycosaminoglycan heparan
sulfate. Such specific heparan sulfates are secreted as
proteoglycans from neural precursor cells and localise to their
surfaces. One such proteoglycan, HSPG-PRM (Perlecan-related
molecule), was isolated through its ability to potentiate
neural cell responses to either FGF-1 or FGF-2. In this study,
we have verified the relative molecular mass of the core
protein of PRM as 45,000 and obtained partial amino acid
sequence from it. The sequences bore significant homology to
native perlecan. A probe generated by reverse transcriptase
polymerase chain reaction using oligonucleotides designed
from the protein sequence used on northern blots of RNA from
a neuroepithelial cell line detected perlecan at 12.6 kilobases,
as well as novel transcripts at 6.5 and 3.5 kilobases. The
latter species appears by virtue of its size and abundance to
be the novel PRM transcript. PRM appears to be encoded by the
same gene as perlecan, as genomic Southern blotting only
detected a single gene. Polyclonal antibodies raised against
the PRM molecule detected a single proteoglycan species at
290x10(3) with a core protein of 45x10(3). Polyclonal anti-
perlecan antibodies cross-reacted with PRM confirming their
relatedness, although immunohistochemical studies revealed a
differential staining pattern for PRM as compared to perlecan
within the developing nervous system. The PRM molecule was
shown to be localised to several different tissues of the
developing embryo, indicating that it plays a broad role. We
conclude that PRM is a variant of perlecan that is
differentially glycosylated in a manner that confers highly
specific functions at critical stages of neural development and
tissue growth.. 0; 0; 0; 143972-95-6; 62031-54-3; 9050-30-
0.
199. Kalcheva, N.; Weidenheim, K. M.; Kress, Y.; Shafit Zagardo, B.
Expression of microtubule-associated protein-2a and other
novel microtubule-associated protein-2 transcripts in human
fetal spinal cord. J-Neurochem. 1997 Jan; 68(1): 383-91; ISSN:
0022-3042.
UNITED-STATES. In human fetal spinal cord (HFSC), six
additional microtubule-associated protein-2 (MAP-2)
transcripts are generated by alternative splicing of two
recently described exons, exon 8 and exon 13. The following
three translated proteins are detected by western blot
analysis: MAP-2b expressing exon 8 (MAP-2b + 8; MAP-2a),
MAP-2b expressing exon 13 (MAP-2b + 13), and MAP-2c
expressing exon 8 and exon 13 (MAP-2c + 8 + 13). The finding
that MAP-2b + 8 is expressed in HFSC demonstrates for the
first time the presence of MAP-2a in human fetal CNS.
Immunocytochemical studies show that exon 8-specific
antibody and exon 13-specific antibody stain independent and
overlapping populations of neurons in the lumbar region of the
HFSC. Antibody 13-immunopositive neurons have
predominantly cytosolic staining, whereas in the antibody 8-
immunoreactive neurons staining was observed in the cytosol,
dendrites, and some synapses. The prenatal expression of MAP-
2a, which has been used as a marker of synaptogenesis, not
only demonstrates the presence of a mature MAP-2 isoform in
HFSC, but suggests that MAP-2a is important during human
fetal as well as postnatal synaptogenesis.. 0; 0.
200. Kalcheva, N.; Weidenheim, K. M.; Kress, Y.; Shafit Zagardo, B.
Expression of microtubule-associated protein-2a and other
novel microtubule-associated protein-2 transcripts in human
fetal spinal cord. J-Neurochem. 1997 Jan; 68(1): 383-91; ISSN:
0022-3042.
UNITED-STATES. In human fetal spinal cord (HFSC), six
additional microtubule-associated protein-2 (MAP-2)
transcripts are generated by alternative splicing of two
recently described exons, exon 8 and exon 13. The following
three translated proteins are detected by western blot
analysis: MAP-2b expressing exon 8 (MAP-2b + 8; MAP-2a),
MAP-2b expressing exon 13 (MAP-2b + 13), and MAP-2c
expressing exon 8 and exon 13 (MAP-2c + 8 + 13). The finding
that MAP-2b + 8 is expressed in HFSC demonstrates for the
first time the presence of MAP-2a in human fetal CNS.
Immunocytochemical studies show that exon 8-specific
antibody and exon 13-specific antibody stain independent and
overlapping populations of neurons in the lumbar region of the
HFSC. Antibody 13-immunopositive neurons have
predominantly cytosolic staining, whereas in the antibody 8-
immunoreactive neurons staining was observed in the cytosol,
dendrites, and some synapses. The prenatal expression of MAP-
2a, which has been used as a marker of synaptogenesis, not
only demonstrates the presence of a mature MAP-2 isoform in
HFSC, but suggests that MAP-2a is important during human
fetal as well as postnatal synaptogenesis.. 0; 0.
201. Kameyama, T.; Hashizume, Y.; Sobue, G. Morphologic features of
the normal human cadaveric spinal cord. Spine. 1996 Jun 1;
21(11): 1285-90; ISSN: 0362-2436.
UNITED-STATES. STUDY DESIGN. The cross-sectional area and
diameter of the normal cadaveric spinal cord at each
segmental level were measured, and the morphologic features
were presented. OBJECTIVES. To provide accurate anatomic
descriptions and morphometric data of the human spinal cord.
SUMMARY OF BACKGROUND DATA. There is a large individual
variation in human spinal cord size, and no authorized standard
of measurement has been established. There have been few
detailed descriptions of the normal morphologic features of
the spinal cord. METHODS. The authors measured the cross-
sectional area and diameter of the spinal cord at each segment
from C2 and S3 in 12 cadaveric specimens, and the
morphologic features of each segment were described.
RESULTS. The relative ratio of the cross-sectional area of
each segment to that of the C3 segment was similar in all the
specimens examined despite a large individual variation in
absolute cord size. Each segment had distinct qualitative and
quantitative morphologic features. CONCLUSIONS. The normal
cross-sectional area of the spinal cord at any segment in an
individual is calculable from measurements of a given single
normal segment. This value appears to be an appropriate and
practical standard of measurement of the normal morphologic
features of the spinal cord.
202. Kameyama, T.; Hashizume, Y.; Sobue, G. Morphologic features of
the normal human cadaveric spinal cord. Spine. 1996 Jun 1;
21(11): 1285-90; ISSN: 0362-2436.
UNITED-STATES. STUDY DESIGN. The cross-sectional area and
diameter of the normal cadaveric spinal cord at each
segmental level were measured, and the morphologic features
were presented. OBJECTIVES. To provide accurate anatomic
descriptions and morphometric data of the human spinal cord.
SUMMARY OF BACKGROUND DATA. There is a large individual
variation in human spinal cord size, and no authorized standard
of measurement has been established. There have been few
detailed descriptions of the normal morphologic features of
the spinal cord. METHODS. The authors measured the cross-
sectional area and diameter of the spinal cord at each segment
from C2 and S3 in 12 cadaveric specimens, and the
morphologic features of each segment were described.
RESULTS. The relative ratio of the cross-sectional area of
each segment to that of the C3 segment was similar in all the
specimens examined despite a large individual variation in
absolute cord size. Each segment had distinct qualitative and
quantitative morphologic features. CONCLUSIONS. The normal
cross-sectional area of the spinal cord at any segment in an
individual is calculable from measurements of a given single
normal segment. This value appears to be an appropriate and
practical standard of measurement of the normal morphologic
features of the spinal cord.
203. Katircioglu, S. F.; Saritas, Z.; Yucel, D.; Bayazit, M.; Tasdemir, O.;
Bayazit, K. Spinal cord protection with the use of prostacyclin
during aortic occlusion. J-Surg-Res. 1996 Sep; 65(1): 77-81;
ISSN: 0022-4804.
UNITED-STATES. This study was planned to investigate if
prostacyclin (PGI2) would reduce spinal cord injury following
aortic occlusion. Twelve dogs underwent 90 min of aortic
occlusion. Six dogs received PGI2 and the remaining animals
did not. PGI2 was administered at a dose of 25 ng/kg/min
during occlusion of the aorta. There were five paraplegic
animals in the control group and one in the PGI2 group 72 hr
after aortic occlusion. Neurological recovery was better in the
PGI2 group than in the control group (P < 0.05).
Malondialdehyde level was 3.55 +/- 0.58 nmole/ml in the PGI2
group and 6.35 +/- 1.27 nmole/ml in the control group 60 min
after aortic cross-clamp removal (P < 0.05). At the same time
interval, protein thiol groups were 629 +/- 50 micromole/L in
the PGI2 group and 376 +/- 69 micromole/L in the control
group (P < 0.05). Distal arterial pressure and central venous
pressure were 15 +/- 4 and 12 +/- 3 mm Hg in the control
group and 33 +/- 5 and 7 +/- 1.6 mm Hg in the PGI2 group,
respectively (P < 0.05). In this study exogenously administered
PGI2 protected the spinal cord from the hazardous effects of
aortic occlusion lasting 90 min.. 0; 35121-78-9; 542-78-9.
204. Katircioglu, S. F.; Saritas, Z.; Yucel, D.; Bayazit, M.; Tasdemir, O.;
Bayazit, K. Spinal cord protection with the use of prostacyclin
during aortic occlusion. J-Surg-Res. 1996 Sep; 65(1): 77-81;
ISSN: 0022-4804.
UNITED-STATES. This study was planned to investigate if
prostacyclin (PGI2) would reduce spinal cord injury following
aortic occlusion. Twelve dogs underwent 90 min of aortic
occlusion. Six dogs received PGI2 and the remaining animals
did not. PGI2 was administered at a dose of 25 ng/kg/min
during occlusion of the aorta. There were five paraplegic
animals in the control group and one in the PGI2 group 72 hr
after aortic occlusion. Neurological recovery was better in the
PGI2 group than in the control group (P < 0.05).
Malondialdehyde level was 3.55 +/- 0.58 nmole/ml in the PGI2
group and 6.35 +/- 1.27 nmole/ml in the control group 60 min
after aortic cross-clamp removal (P < 0.05). At the same time
interval, protein thiol groups were 629 +/- 50 micromole/L in
the PGI2 group and 376 +/- 69 micromole/L in the control
group (P < 0.05). Distal arterial pressure and central venous
pressure were 15 +/- 4 and 12 +/- 3 mm Hg in the control
group and 33 +/- 5 and 7 +/- 1.6 mm Hg in the PGI2 group,
respectively (P < 0.05). In this study exogenously administered
PGI2 protected the spinal cord from the hazardous effects of
aortic occlusion lasting 90 min.. 0; 35121-78-9; 542-78-9.
205. Katter, J. T.; Dado, R. J.; Kostarczyk, E.; Giesler, GJ Jr.
Spinothalamic and spinohypothalamic tract neurons in the
sacral spinal cord of rats. II. Responses to cutaneous and
visceral stimuli. J-Neurophysiol. 1996 Jun; 75(6): 2606-28;
ISSN: 0022-3077.
UNITED-STATES. 1. A goal of this study was to determine
whether neurons in the sacral spinal cord that project to the
diencephalon are involved in the processing and transmission
of sensory information that arises in the perineum and pelvis.
Therefore, 58 neurons in segments L6-S2 were activated
antidromically with currents < or = 30 microA from points in
the contralateral diencephalon in rats that were anesthetized
with urethan. 2. Responses to mechanical stimuli applied to
the cutaneous receptive fields of these neurons were used to
classify them as low-threshold (LT), wide dynamic range
(WDR) or high-threshold (HT) neurons. Twenty-two neurons
(38%) responded preferentially to brushing (LT neurons).
Eighteen neurons (31%) responded to brushing but responded
with higher firing frequencies to noxious mechanical stimuli
(WDR neurons). Eighteen neurons (31%) responded only to
noxious intensities of mechanical stimulation (HT neurons). LT
neurons were recorded predominantly in nucleus proprius of
the dorsal horn. Nociceptive neurons (WDR and HT) were
recorded throughout the dorsal horn. 3. Cutaneous receptive
fields were mapped for 56 neurons. Forty-five (80%) had
receptive fields that included at least two of the following
regions ipsilaterally: the rump, perineum, or tail. Eleven
neurons (20%) had receptive fields that were restricted to one
of these areas or to the ipsilateral hind limb. Thirty-eight
neurons (68%) had cutaneous receptive fields that also
included regions of the contralateral tail or perineum. On the
perineum, receptive fields usually encompassed perianal and
perivaginal areas including the clitoral sheath. There were no
statistically significant differences in the locations or sizes
of receptive fields for LT neurons compared with nociceptive
(WDR and HT) neurons. 4. Thirty-seven LT, WDR, and HT neurons
were tested for their responsiveness to heat stimuli. Five
(14%) responded to increasing intensities of heat with graded
increases in their firing frequencies. Thirty-two LT, WDR, and
HT neurons also were tested with cold stimuli. None responded
with graded increases in their firing frequencies to
increasingly colder stimuli. There were no statistically
significant differences among the responses of LT, WDR, and
HT neurons to either heat or cold stimuli. 5. Forty LT, WDR, and
HT neurons were tested for their responsiveness to visceral
stimuli by distending a balloon placed into the rectum and
colon with a series of increasing pressures. Seventeen (43%)
exhibited graded increases in their firing frequencies in
response to increasing pressures of colorectal distention
(CrD). None of the responsive neurons responded reproducibly
to CrD at an intensity of 20 mmHg, and all responded at
intensities of > or = 80 mmHg. More than 90% responded
abruptly at stimulus onset, responded continuously throughout
the stimulus period, and stopped responding immediately after
termination of the stimulus. 6. Thirty-one neurons were tested
for their responsiveness to distention of a balloon placed
inside the vagina. Eleven (35%) exhibited graded increases in
their firing frequencies in response to increasing pressures of
vaginal distention (VaD). The thresholds and temporal profiles
of the responses to VaD were similar to those for CrD.
Twenty-nine neurons were tested with both CrD and VaD.
Thirteen (45%) were excited by both stimuli, four (14%)
responded to CrD but not VaD, and one (3%) was excited by VaD
but not CrD. Neurons excited by CrD, VaD, or both were
recorded throughout the dorsal horn. 7. As a population, WDR
neurons, but not LT or HT neurons, encoded increasing
pressures of CrD and VaD with graded increases in their firing
frequencies. The responses of WDR neurons to CrD differed
significantly from those of either LT or HT neurons. Regression
analyses of the stimulus-response functions of responsive
WDR neurons to CrD and VaD were described by power
functions with exponents of 1.6 and 2.4,
respectively.(ABSTRACT TRUNCATED).
206. Katter, J. T.; Dado, R. J.; Kostarczyk, E.; Giesler, GJ Jr.
Spinothalamic and spinohypothalamic tract neurons in the
sacral spinal cord of rats. I. Locations of antidromically
identified axons in the cervical cord and diencephalon. J-
Neurophysiol. 1996 Jun; 75(6): 2581-605; ISSN: 0022-3077.
UNITED-STATES. 1. A goal of this study was to determine the
sites in the diencephalon to which neurons in sacral spinal
segments of rats project. Therefore, 95 neurons were recorded
extracellularly in spinal segments L6-S2 of rats that were
anesthetized with urethan. These neurons were activated
initially antidromically with currents < or = 30 microA from a
monopolar stimulating electrode placed into the contralateral
posterior diencephalon. The mean +/- SE current for
antidromic activation from these sites was 16 +/- 0.8 microA.
These neurons were recorded in the superficial dorsal horn
(4%), deep dorsal horn (89%), and intermediate zone and
ventral horn (4%). 2. Systematic antidromic mapping
techniques were used to map the axonal projections of 41 of
these neurons within the diencephalon. Thirty-three neurons
(80%) could be activated antidromically with currents < or =
30 microA only from points in the contralateral thalamus and
are referred to as spinothalamic tract (STT) neurons. Eight
neurons (20%) were activated antidromically with low
currents from points in both the contralateral thalamus and
hypothalamus, and these neurons are referred to as
spinothalamic tract/ spinohypothalamic tract (STT/SHT)
neurons. Three additional neurons were activated
antidromically with currents < or = 30 microA only from
points within the contralateral hypothalamus and are referred
to as spinohypothalamic tract (SHT) neurons. The diencephalic
projections of another 51 neurons were mapped incompletely.
These neurons are referred to as spinothalamic/unknown (STT/
U) neurons to indicate that it was not known whether their
axons ascended beyond the site in the thalamus from which
they initially were activated antidromically. 3. For 31 STT
neurons, the most anterior point at which antidromic
activation was achieved with currents < or = 30 microA was
determined. Fourteen (45%) were activated antidromically only
from sites posterior to the ventrobasal complex (VbC) of the
thalamus. Sixteen STT neurons (52%) were activated
antidromically with low currents from sites at the level of
the VbC, but not from more anterior levels. One STT neuron
(3%) was activated antidromically from the anteroventral
nucleus of the thalamus. 4. STT/SHT neurons were
antidromically activated with currents < or = 30 microA from
the medial lemniscus (ML), anterior pretectal nucleus (APt),
posterior nuclear group and medial geniculate nucleus (Po/MG),
and zona incerta in the thalamus and from the optic tract (OT),
supraoptic decussation, or lateral area of the hypothalamus. No
differences in the sites in the thalamus from which STT and
STT/SHT neurons were activated antidromically were
apparent. Five STT/SHT neurons (62%) were activated
antidromically from points in the thalamus in the posterior
diencephalon and from points in the hypothalamus at more
anterior levels. Three STT/SHT neurons (38%) were activated
antidromically with currents < or = 30 microA from sites in
both the thalamus and hypothalamus at the same anterior-
posterior level of the diencephalon. All three of these STT/SHT
neurons projected to the intralaminar nuclei (parafascicular or
central lateral nuclei) of the thalamus. 5. Seven STT/SHT
neurons were tested for additional projections to the
ipsilateral brain. Two (29%) were activated antidromically
with currents < or = 30 microA and at longer latencies from
sites in the ipsilateral diencephalon. One could only be
activated antidromically from the hypothalamus ipsilaterally.
The other was activated antidromically at progressively
increasing latencies from points in the ipsilateral brain that
extended as far posteriorly as the posterior pole of the MG. 6.
Fifty-eight STT, STT/SHT, and STT/U neurons were classified
as low-threshold (LT), wide dynamic range (WDR), or
highthreshold (HT) neurons based on their responsiveness to
innocuous and noxious mechanical stimuli applied to their
cutaneous receptive fields.(ABSTRACT TRUNCATED).
207. Katter, J. T.; Dado, R. J.; Kostarczyk, E.; Giesler, GJ Jr.
Spinothalamic and spinohypothalamic tract neurons in the
sacral spinal cord of rats. II. Responses to cutaneous and
visceral stimuli. J-Neurophysiol. 1996 Jun; 75(6): 2606-28;
ISSN: 0022-3077.
UNITED-STATES. 1. A goal of this study was to determine
whether neurons in the sacral spinal cord that project to the
diencephalon are involved in the processing and transmission
of sensory information that arises in the perineum and pelvis.
Therefore, 58 neurons in segments L6-S2 were activated
antidromically with currents < or = 30 microA from points in
the contralateral diencephalon in rats that were anesthetized
with urethan. 2. Responses to mechanical stimuli applied to
the cutaneous receptive fields of these neurons were used to
classify them as low-threshold (LT), wide dynamic range
(WDR) or high-threshold (HT) neurons. Twenty-two neurons
(38%) responded preferentially to brushing (LT neurons).
Eighteen neurons (31%) responded to brushing but responded
with higher firing frequencies to noxious mechanical stimuli
(WDR neurons). Eighteen neurons (31%) responded only to
noxious intensities of mechanical stimulation (HT neurons). LT
neurons were recorded predominantly in nucleus proprius of
the dorsal horn. Nociceptive neurons (WDR and HT) were
recorded throughout the dorsal horn. 3. Cutaneous receptive
fields were mapped for 56 neurons. Forty-five (80%) had
receptive fields that included at least two of the following
regions ipsilaterally: the rump, perineum, or tail. Eleven
neurons (20%) had receptive fields that were restricted to one
of these areas or to the ipsilateral hind limb. Thirty-eight
neurons (68%) had cutaneous receptive fields that also
included regions of the contralateral tail or perineum. On the
perineum, receptive fields usually encompassed perianal and
perivaginal areas including the clitoral sheath. There were no
statistically significant differences in the locations or sizes
of receptive fields for LT neurons compared with nociceptive
(WDR and HT) neurons. 4. Thirty-seven LT, WDR, and HT neurons
were tested for their responsiveness to heat stimuli. Five
(14%) responded to increasing intensities of heat with graded
increases in their firing frequencies. Thirty-two LT, WDR, and
HT neurons also were tested with cold stimuli. None responded
with graded increases in their firing frequencies to
increasingly colder stimuli. There were no statistically
significant differences among the responses of LT, WDR, and
HT neurons to either heat or cold stimuli. 5. Forty LT, WDR, and
HT neurons were tested for their responsiveness to visceral
stimuli by distending a balloon placed into the rectum and
colon with a series of increasing pressures. Seventeen (43%)
exhibited graded increases in their firing frequencies in
response to increasing pressures of colorectal distention
(CrD). None of the responsive neurons responded reproducibly
to CrD at an intensity of 20 mmHg, and all responded at
intensities of > or = 80 mmHg. More than 90% responded
abruptly at stimulus onset, responded continuously throughout
the stimulus period, and stopped responding immediately after
termination of the stimulus. 6. Thirty-one neurons were tested
for their responsiveness to distention of a balloon placed
inside the vagina. Eleven (35%) exhibited graded increases in
their firing frequencies in response to increasing pressures of
vaginal distention (VaD). The thresholds and temporal profiles
of the responses to VaD were similar to those for CrD.
Twenty-nine neurons were tested with both CrD and VaD.
Thirteen (45%) were excited by both stimuli, four (14%)
responded to CrD but not VaD, and one (3%) was excited by VaD
but not CrD. Neurons excited by CrD, VaD, or both were
recorded throughout the dorsal horn. 7. As a population, WDR
neurons, but not LT or HT neurons, encoded increasing
pressures of CrD and VaD with graded increases in their firing
frequencies. The responses of WDR neurons to CrD differed
significantly from those of either LT or HT neurons. Regression
analyses of the stimulus-response functions of responsive
WDR neurons to CrD and VaD were described by power
functions with exponents of 1.6 and 2.4,
respectively.(ABSTRACT TRUNCATED).
208. Katter, J. T.; Dado, R. J.; Kostarczyk, E.; Giesler, GJ Jr.
Spinothalamic and spinohypothalamic tract neurons in the
sacral spinal cord of rats. I. Locations of antidromically
identified axons in the cervical cord and diencephalon. J-
Neurophysiol. 1996 Jun; 75(6): 2581-605; ISSN: 0022-3077.
UNITED-STATES. 1. A goal of this study was to determine the
sites in the diencephalon to which neurons in sacral spinal
segments of rats project. Therefore, 95 neurons were recorded
extracellularly in spinal segments L6-S2 of rats that were
anesthetized with urethan. These neurons were activated
initially antidromically with currents < or = 30 microA from a
monopolar stimulating electrode placed into the contralateral
posterior diencephalon. The mean +/- SE current for
antidromic activation from these sites was 16 +/- 0.8 microA.
These neurons were recorded in the superficial dorsal horn
(4%), deep dorsal horn (89%), and intermediate zone and
ventral horn (4%). 2. Systematic antidromic mapping
techniques were used to map the axonal projections of 41 of
these neurons within the diencephalon. Thirty-three neurons
(80%) could be activated antidromically with currents < or =
30 microA only from points in the contralateral thalamus and
are referred to as spinothalamic tract (STT) neurons. Eight
neurons (20%) were activated antidromically with low
currents from points in both the contralateral thalamus and
hypothalamus, and these neurons are referred to as
spinothalamic tract/ spinohypothalamic tract (STT/SHT)
neurons. Three additional neurons were activated
antidromically with currents < or = 30 microA only from
points within the contralateral hypothalamus and are referred
to as spinohypothalamic tract (SHT) neurons. The diencephalic
projections of another 51 neurons were mapped incompletely.
These neurons are referred to as spinothalamic/unknown (STT/
U) neurons to indicate that it was not known whether their
axons ascended beyond the site in the thalamus from which
they initially were activated antidromically. 3. For 31 STT
neurons, the most anterior point at which antidromic
activation was achieved with currents < or = 30 microA was
determined. Fourteen (45%) were activated antidromically only
from sites posterior to the ventrobasal complex (VbC) of the
thalamus. Sixteen STT neurons (52%) were activated
antidromically with low currents from sites at the level of
the VbC, but not from more anterior levels. One STT neuron
(3%) was activated antidromically from the anteroventral
nucleus of the thalamus. 4. STT/SHT neurons were
antidromically activated with currents < or = 30 microA from
the medial lemniscus (ML), anterior pretectal nucleus (APt),
posterior nuclear group and medial geniculate nucleus (Po/MG),
and zona incerta in the thalamus and from the optic tract (OT),
supraoptic decussation, or lateral area of the hypothalamus. No
differences in the sites in the thalamus from which STT and
STT/SHT neurons were activated antidromically were
apparent. Five STT/SHT neurons (62%) were activated
antidromically from points in the thalamus in the posterior
diencephalon and from points in the hypothalamus at more
anterior levels. Three STT/SHT neurons (38%) were activated
antidromically with currents < or = 30 microA from sites in
both the thalamus and hypothalamus at the same anterior-
posterior level of the diencephalon. All three of these STT/SHT
neurons projected to the intralaminar nuclei (parafascicular or
central lateral nuclei) of the thalamus. 5. Seven STT/SHT
neurons were tested for additional projections to the
ipsilateral brain. Two (29%) were activated antidromically
with currents < or = 30 microA and at longer latencies from
sites in the ipsilateral diencephalon. One could only be
activated antidromically from the hypothalamus ipsilaterally.
The other was activated antidromically at progressively
increasing latencies from points in the ipsilateral brain that
extended as far posteriorly as the posterior pole of the MG. 6.
Fifty-eight STT, STT/SHT, and STT/U neurons were classified
as low-threshold (LT), wide dynamic range (WDR), or
highthreshold (HT) neurons based on their responsiveness to
innocuous and noxious mechanical stimuli applied to their
cutaneous receptive fields.(ABSTRACT TRUNCATED).
209. Katz, P. S. Neurons, networks, and motor behavior. Neuron. 1996
Feb; 16(2): 245-53; ISSN: 0896-6273.
UNITED-STATES. The field of motor pattern generation and
motor control has progressed markedly in the last decade.
There has been a revolutionary shift in thinking from hard-
wired circuits to multifunctional networks. Yet, it is clear
that we still have a long way to go before we understand how
very large ensembles of neurons produce behaviors. The
systems where we have made the most headway are those that
have an orderly topography, such as the superior colliculus
(Sparks) or motor cortex (Georgopoulos). However, even in
these systems, although we understand how to interpret the
combined activity of the neuronal population, it is not clear
how this population activity is translated into a motor
command. Similarly, the directional behavior produced in
cockroach (Ritzmann) and fish escape (Eaton) systems can be
predicted based on the activity of neurons, but the cellular
mechanisms producing the turning responses in cockroaches
and teleost fish are not completely understood. Undoubtedly,
computational approaches, including new mathematical
formalisms and computer simulations, will play a role in
elucidating how very large ensembles of neurons produce their
coordinated output. For now, the systems where motor pattern
generation is best understood at the cellular level are those
with small numbers of neurons (such as invertebrate circuits)
or small numbers of cell types, such as lamprey and tadpole
spinal circuits. These systems are thus valuable for pointing
to potential mechanisms used in larger systems. (Note that I
avoid using the term "simple" systems to describe
invertebrates because it is quite clear that these systems are
anything but simple.) However, "interphyletic awareness," as it
was referred to at this conference, is not important just for
what it can tell us about how mammals work. It is also
important to learn of alternative ways in which organisms
solve similar problems. This may prove to be particularly
important for the future of robotics. Already, robots have been
designed based on insights gained from studying insect visual
(Strausfeld) and motor (Ritzmann) systems. Robotics engineers
have also independently converged on some of the same
mechanisms used by biological systems (MacPherson). There is
clearly a need for better understanding of higher control of
pattern-generating circuits. This is not limited to how motor
patterns are initiated, but also includes how they are altered
on a moment to moment basis to suit the needs of the animal.
The next revolution in the field is likely to come from a
paradigm shift regarding such control of motor circuits,
similar to the shift that has already occurred in our
understanding of the pattern-generating circuits themselves.
Such flexibility of control is the basis for decision making in
the nervous system and the very essence of what animals must
do throughout their daily lives. I look forward to the next
conference in 2005 to see how far we've progressed in these
pursuits.. 0.
210. Katz, P. S. Neurons, networks, and motor behavior. Neuron. 1996
Feb; 16(2): 245-53; ISSN: 0896-6273.
UNITED-STATES. The field of motor pattern generation and
motor control has progressed markedly in the last decade.
There has been a revolutionary shift in thinking from hard-
wired circuits to multifunctional networks. Yet, it is clear
that we still have a long way to go before we understand how
very large ensembles of neurons produce behaviors. The
systems where we have made the most headway are those that
have an orderly topography, such as the superior colliculus
(Sparks) or motor cortex (Georgopoulos). However, even in
these systems, although we understand how to interpret the
combined activity of the neuronal population, it is not clear
how this population activity is translated into a motor
command. Similarly, the directional behavior produced in
cockroach (Ritzmann) and fish escape (Eaton) systems can be
predicted based on the activity of neurons, but the cellular
mechanisms producing the turning responses in cockroaches
and teleost fish are not completely understood. Undoubtedly,
computational approaches, including new mathematical
formalisms and computer simulations, will play a role in
elucidating how very large ensembles of neurons produce their
coordinated output. For now, the systems where motor pattern
generation is best understood at the cellular level are those
with small numbers of neurons (such as invertebrate circuits)
or small numbers of cell types, such as lamprey and tadpole
spinal circuits. These systems are thus valuable for pointing
to potential mechanisms used in larger systems. (Note that I
avoid using the term "simple" systems to describe
invertebrates because it is quite clear that these systems are
anything but simple.) However, "interphyletic awareness," as it
was referred to at this conference, is not important just for
what it can tell us about how mammals work. It is also
important to learn of alternative ways in which organisms
solve similar problems. This may prove to be particularly
important for the future of robotics. Already, robots have been
designed based on insights gained from studying insect visual
(Strausfeld) and motor (Ritzmann) systems. Robotics engineers
have also independently converged on some of the same
mechanisms used by biological systems (MacPherson). There is
clearly a need for better understanding of higher control of
pattern-generating circuits. This is not limited to how motor
patterns are initiated, but also includes how they are altered
on a moment to moment basis to suit the needs of the animal.
The next revolution in the field is likely to come from a
paradigm shift regarding such control of motor circuits,
similar to the shift that has already occurred in our
understanding of the pattern-generating circuits themselves.
Such flexibility of control is the basis for decision making in
the nervous system and the very essence of what animals must
do throughout their daily lives. I look forward to the next
conference in 2005 to see how far we've progressed in these
pursuits.. 0.
211. Kawakami, Y.; Oshima, T. Long-lasting potentiation in the
secondary somatosensory cortex affects motor control:
assessment by H-reflex. Neuroscience. 1996 Oct; 74(4): 1125-
33; ISSN: 0306-4522.
UNITED-STATES. We investigated descending projections from
the secondary somatosensory cortex to the feline spinal cord
and the effects of long-lasting potentiation in secondary
somatosensory cortex on the activities of motoneurons of the
cat. Electrophysiological examinations revealed that the low-
intensity subthreshold secondary somatosensory cortex
stimulation could change the H-Reflex induced by radial nerve
stimulation. The H-wave amplitudes, recorded in wrist flexor
muscles, were enhanced when the intervals from secondary
somatosensory cortex to radial nerve stimuli were altered
from 0 to 30 ms (initial excitation, 146 +/- 11% (mean +/-
S.E.M.) of the control value). In contrast, the H-waves were
suppressed with intervals longer than 30 ms (80 +/- 3%). The
descending pathways from secondary somatosensory cortex to
the spinal cord were assessed using an immunohistochemical
technique. c-Fos and Zif268 proteins, induced by stimulation
of the hand-represented secondary somatosensory cortex
areas, could thus express in activated cervical neurons. The
density of labeled cells was significantly higher in the
seventh and eighth cervical segments than in other levels. The
great majority of positive cells were distributed in the lateral
part of the contralateral ventral horn and their somas ranged
from 10 to 50 microns in size. Finally, we examined the
effects of long-lasting potentiation, induced by high-
frequency stimulation of the ventral posterolateral thalamic
nucleus, on the activities of spinal motoneurons. Long-lasting
potentiation altered the previously observed effects of
secondary somatosensory cortex stimulation on the H-wave
amplitude. The secondary somatosensory cortex-conditioned
initial excitation of the H-reflex was enhanced (from 139 to
175%, P < 0.05), while late suppression was completely
blocked (from 74 to 112%, P < 0.01). In conclusion, the
descending pathways from secondary somatosensory cortex to
the spinal cord modulated the H-reflex, and long-lasting
potentiation in secondary somatosensory cortex affected this
modulation. We have previously reported that corticocortical
inputs from primary to secondary somatosensory cortex is
required for induction of long-lasting potentiation in
secondary somatosensory cortex. Taken together, the present
study suggests that cortical plasticity in secondary
somatosensory cortex amplifies somatic inputs from primary
somatosensory cortex as a means of adaptive motor control by
the sensory system.. 0; 0; 0; 0.
212. Kawakami, Y.; Oshima, T. Long-lasting potentiation in the
secondary somatosensory cortex affects motor control:
assessment by H-reflex. Neuroscience. 1996 Oct; 74(4): 1125-
33; ISSN: 0306-4522.
UNITED-STATES. We investigated descending projections from
the secondary somatosensory cortex to the feline spinal cord
and the effects of long-lasting potentiation in secondary
somatosensory cortex on the activities of motoneurons of the
cat. Electrophysiological examinations revealed that the low-
intensity subthreshold secondary somatosensory cortex
stimulation could change the H-Reflex induced by radial nerve
stimulation. The H-wave amplitudes, recorded in wrist flexor
muscles, were enhanced when the intervals from secondary
somatosensory cortex to radial nerve stimuli were altered
from 0 to 30 ms (initial excitation, 146 +/- 11% (mean +/-
S.E.M.) of the control value). In contrast, the H-waves were
suppressed with intervals longer than 30 ms (80 +/- 3%). The
descending pathways from secondary somatosensory cortex to
the spinal cord were assessed using an immunohistochemical
technique. c-Fos and Zif268 proteins, induced by stimulation
of the hand-represented secondary somatosensory cortex
areas, could thus express in activated cervical neurons. The
density of labeled cells was significantly higher in the
seventh and eighth cervical segments than in other levels. The
great majority of positive cells were distributed in the lateral
part of the contralateral ventral horn and their somas ranged
from 10 to 50 microns in size. Finally, we examined the
effects of long-lasting potentiation, induced by high-
frequency stimulation of the ventral posterolateral thalamic
nucleus, on the activities of spinal motoneurons. Long-lasting
potentiation altered the previously observed effects of
secondary somatosensory cortex stimulation on the H-wave
amplitude. The secondary somatosensory cortex-conditioned
initial excitation of the H-reflex was enhanced (from 139 to
175%, P < 0.05), while late suppression was completely
blocked (from 74 to 112%, P < 0.01). In conclusion, the
descending pathways from secondary somatosensory cortex to
the spinal cord modulated the H-reflex, and long-lasting
potentiation in secondary somatosensory cortex affected this
modulation. We have previously reported that corticocortical
inputs from primary to secondary somatosensory cortex is
required for induction of long-lasting potentiation in
secondary somatosensory cortex. Taken together, the present
study suggests that cortical plasticity in secondary
somatosensory cortex amplifies somatic inputs from primary
somatosensory cortex as a means of adaptive motor control by
the sensory system.. 0; 0; 0; 0.
213. Keil, GJ 2nd; DeLander, G. E. Altered sensory behaviors in mice
following manipulation of endogenous spinal adenosine
neurotransmission. Eur-J-Pharmacol. 1996 Sep 19; 312(1): 7-
14; ISSN: 0014-2999.
NETHERLANDS. Adenosine or adenosine analogs injected
intrathecally (i.t.) induce significant antinociception. Recent
studies support the existence of an endogenous spinal system
that can modulate nociceptive input by releasing adenosine.
Inhibition of adenosine metabolism by administration of an
adenosine kinase inhibitor, in the present study, decreased
behavior induced by putative pain neurotransmitters providing
additional support for an endogenous purinergic system.
Conversely, administration of high doses of methylxanthines
(i.t.), adenosine receptor antagonists, induced behavior similar
to that induced by pain neurotransmitters. Methylxanthine
(i.t.)-induced behavior was partially inhibited by antagonists
of receptors for pain neurotransmitters. These observations
are consistent with the hypothesis that an endogenous
purinergic system tonically modulates nociceptive input
involving a variety of chemical mediators. Preliminary studies
also revealed methylxanthine-induced allodynia and suggested
spinal purinergic systems may have a broader role in
discriminating sensory input.. 0; 0; 14365-44-7; 33507-63-0;
41552-82-3; 58-55-9; 58-61-7; 91224-37-2.
214. Keil, GJ 2nd; DeLander, G. E. Altered sensory behaviors in mice
following manipulation of endogenous spinal adenosine
neurotransmission. Eur-J-Pharmacol. 1996 Sep 19; 312(1): 7-
14; ISSN: 0014-2999.
NETHERLANDS. Adenosine or adenosine analogs injected
intrathecally (i.t.) induce significant antinociception. Recent
studies support the existence of an endogenous spinal system
that can modulate nociceptive input by releasing adenosine.
Inhibition of adenosine metabolism by administration of an
adenosine kinase inhibitor, in the present study, decreased
behavior induced by putative pain neurotransmitters providing
additional support for an endogenous purinergic system.
Conversely, administration of high doses of methylxanthines
(i.t.), adenosine receptor antagonists, induced behavior similar
to that induced by pain neurotransmitters. Methylxanthine
(i.t.)-induced behavior was partially inhibited by antagonists
of receptors for pain neurotransmitters. These observations
are consistent with the hypothesis that an endogenous
purinergic system tonically modulates nociceptive input
involving a variety of chemical mediators. Preliminary studies
also revealed methylxanthine-induced allodynia and suggested
spinal purinergic systems may have a broader role in
discriminating sensory input.. 0; 0; 14365-44-7; 33507-63-0;
41552-82-3; 58-55-9; 58-61-7; 91224-37-2.
215. Keino Masu, K.; Masu, M.; Hinck, L.; Leonardo, E. D.; Chan, S. S.;
Culotti, J. G.; Tessier Lavigne, M. Deleted in Colorectal Cancer
(DCC) encodes a netrin receptor. Cell. 1996 Oct 18; 87(2): 175-
85; ISSN: 0092-8674.
UNITED-STATES. The guidance of developing axons in the
nervous system is mediated partly by diffusible
chemoattractants secreted by axonal target cells. Netrins are
chemoattractants for commissural axons in the vertebrate
spinal cord, but the mechanisms through which they produce
their effects are unknown. We show that Deleted in Colorectal
Cancer (DCC), a transmembrane protein of the immunoglobulin
superfamily, is expressed on spinal commissural axons and
possesses netrin-1-binding activity. Moreover, an antibody to
DCC selectively blocks the netrin-1-dependent outgrowth of
commissural axons in vitro. These results indicate that DCC is
a receptor or a component of a receptor that mediates the
effects of netrin-1 on commissural axons, and they
complement genetic evidence for interactions between DCC
and netrin homologs in C. elegans and Drosophila.. 0; 0; 0; 0; 0;
0; 0; 0; 158651-98-0.
216. Keino Masu, K.; Masu, M.; Hinck, L.; Leonardo, E. D.; Chan, S. S.;
Culotti, J. G.; Tessier Lavigne, M. Deleted in Colorectal Cancer
(DCC) encodes a netrin receptor. Cell. 1996 Oct 18; 87(2): 175-
85; ISSN: 0092-8674.
UNITED-STATES. The guidance of developing axons in the
nervous system is mediated partly by diffusible
chemoattractants secreted by axonal target cells. Netrins are
chemoattractants for commissural axons in the vertebrate
spinal cord, but the mechanisms through which they produce
their effects are unknown. We show that Deleted in Colorectal
Cancer (DCC), a transmembrane protein of the immunoglobulin
superfamily, is expressed on spinal commissural axons and
possesses netrin-1-binding activity. Moreover, an antibody to
DCC selectively blocks the netrin-1-dependent outgrowth of
commissural axons in vitro. These results indicate that DCC is
a receptor or a component of a receptor that mediates the
effects of netrin-1 on commissural axons, and they
complement genetic evidence for interactions between DCC
and netrin homologs in C. elegans and Drosophila.. 0; 0; 0; 0; 0;
0; 0; 0; 158651-98-0.
217. Kimura, A.; Sato, A.; Sato, Y.; Suzuki, H. A- and C-reflexes elicited
in cardiac sympathetic nerves by single shock to a somatic
afferent nerve include spinal and supraspinal components in
anesthetized rats. Neurosci-Res. 1996 May; 25(1): 91-6; ISSN:
0168-0102.
IRELAND. The spinal and supraspinal components of both A-
and C-reflexes were studied in the somato-cardiac
sympathetic reflex discharges elicited by a single electrical
shock either to a spinal (T3-4) afferent nerve or to a limb
(tibial) afferent nerve in urethane anesthetized rats. In central
nervous system (CNS) intact rats, a single shock to a T3-4
spinal afferent nerve produced early and late A-reflex
discharges with latencies of 20 +/- 1 ms and 62 +/- 6 ms,
respectively, and a C-reflex with a latency of 136 +/- 9 ms in
a cardiac sympathetic efferent nerve. After spinalization at
the first cervical level, stimulation of the same spinal
afferent nerve produced an A-reflex with the same latency as
the early A-reflex in CNS-intact rats and a C-reflex with a
latency of 86 +/- 3 ms. The amplitude of the early A-reflex
became augmented after spinal transection. On the other hand,
a single shock to a tibial afferent nerve evoked an A-reflex
discharge with a latency of 41 +/- 2 ms and a C-reflex
discharge with a latency of 210 +/- 13 ms in CNS-intact rats.
These A- and C-reflexes elicited by stimulation of a tibial
afferent nerve were not observed after spinalization. It was
concluded that cardiac sympathetic A- and C-reflex discharges
evoked by stimulation of a segmental spinal afferent nerve in
CNS-intact rats are of spinal and supraspinal origin, and those
evoked by tibial nerve stimulation are of supraspinal origin.
The spinal reflex pathway is segmentally organized, because
the spinal reflex is evoked only when stimulation is delivered
to afferent nerves close to the cardiac sympathetic outflow
segments. With the CNS intact, the spinal reflex component is
depressed by descending inhibitory pathways originating in the
brain.
218. Kimura, A.; Sato, A.; Sato, Y.; Suzuki, H. A- and C-reflexes elicited
in cardiac sympathetic nerves by single shock to a somatic
afferent nerve include spinal and supraspinal components in
anesthetized rats. Neurosci-Res. 1996 May; 25(1): 91-6; ISSN:
0168-0102.
IRELAND. The spinal and supraspinal components of both A-
and C-reflexes were studied in the somato-cardiac
sympathetic reflex discharges elicited by a single electrical
shock either to a spinal (T3-4) afferent nerve or to a limb
(tibial) afferent nerve in urethane anesthetized rats. In central
nervous system (CNS) intact rats, a single shock to a T3-4
spinal afferent nerve produced early and late A-reflex
discharges with latencies of 20 +/- 1 ms and 62 +/- 6 ms,
respectively, and a C-reflex with a latency of 136 +/- 9 ms in
a cardiac sympathetic efferent nerve. After spinalization at
the first cervical level, stimulation of the same spinal
afferent nerve produced an A-reflex with the same latency as
the early A-reflex in CNS-intact rats and a C-reflex with a
latency of 86 +/- 3 ms. The amplitude of the early A-reflex
became augmented after spinal transection. On the other hand,
a single shock to a tibial afferent nerve evoked an A-reflex
discharge with a latency of 41 +/- 2 ms and a C-reflex
discharge with a latency of 210 +/- 13 ms in CNS-intact rats.
These A- and C-reflexes elicited by stimulation of a tibial
afferent nerve were not observed after spinalization. It was
concluded that cardiac sympathetic A- and C-reflex discharges
evoked by stimulation of a segmental spinal afferent nerve in
CNS-intact rats are of spinal and supraspinal origin, and those
evoked by tibial nerve stimulation are of supraspinal origin.
The spinal reflex pathway is segmentally organized, because
the spinal reflex is evoked only when stimulation is delivered
to afferent nerves close to the cardiac sympathetic outflow
segments. With the CNS intact, the spinal reflex component is
depressed by descending inhibitory pathways originating in the
brain.
219. Kitao, Y.; Robertson, B.; Kudo, M.; Grant, G. Neurogenesis of
subpopulations of rat lumbar dorsal root ganglion neurons
including neurons projecting to the dorsal column nuclei. J-
Comp-Neurol. 1996 Jul 22; 371(2): 249-57; ISSN: 0021-9967.
UNITED-STATES. The time of birth of subpopulations of dorsal
root ganglion (DRG) neurons was studied with
immunohistochemistry for 5-bromodeoxyuridine (BrdU).
Pregnant rats were injected with BrdU i.p. to label the neurons
on one of the embryonic days (E) E11-E16. When they were
adults, the rats were given injections of Fluoro-Gold (FG) into
the gracile nucleus to identify DRG neurons projecting to this
structure. Following a 5 day survival period, the animals were
perfused with aldehyde fixative. Sections from the L3-L5 DRGs
were processed for BrdU immunohistochemistry followed by
either immunostaining for the antineurofilament antibody
RT97, as marker of the light neuronal subpopulation, or
histochemical staining for the B4 isolectin from Griffonia
simplicifolia I, as marker of the small dark subpopulation. The
results indicated that the DRG neurons were generated
between E12 and E16. The RT97+ neurons were generated on
E12-E15, with a peak at E13. FG+ neurons, the majority of
which were RT97+, were also generated on E12-E15. The B4+
neurons were generated on E13-E16, with a peak around E14.
The overall pattern of neurogenesis of the DRG neurons showed
that the RT97+ neurons were produced prior to the B4+
neurons. These findings are in agreement with earlier
observations that the large DRG neurons are generated earlier
than the small dark neurons. Our findings also suggest the
existence of a third neuronal subpopulation that might be
produced at the latest period of DRG neurogenesis at E15-E16..
0; 59-14-3; 82785-14-6.
220. Kitao, Y.; Robertson, B.; Kudo, M.; Grant, G. Neurogenesis of
subpopulations of rat lumbar dorsal root ganglion neurons
including neurons projecting to the dorsal column nuclei. J-
Comp-Neurol. 1996 Jul 22; 371(2): 249-57; ISSN: 0021-9967.
UNITED-STATES. The time of birth of subpopulations of dorsal
root ganglion (DRG) neurons was studied with
immunohistochemistry for 5-bromodeoxyuridine (BrdU).
Pregnant rats were injected with BrdU i.p. to label the neurons
on one of the embryonic days (E) E11-E16. When they were
adults, the rats were given injections of Fluoro-Gold (FG) into
the gracile nucleus to identify DRG neurons projecting to this
structure. Following a 5 day survival period, the animals were
perfused with aldehyde fixative. Sections from the L3-L5 DRGs
were processed for BrdU immunohistochemistry followed by
either immunostaining for the antineurofilament antibody
RT97, as marker of the light neuronal subpopulation, or
histochemical staining for the B4 isolectin from Griffonia
simplicifolia I, as marker of the small dark subpopulation. The
results indicated that the DRG neurons were generated
between E12 and E16. The RT97+ neurons were generated on
E12-E15, with a peak at E13. FG+ neurons, the majority of
which were RT97+, were also generated on E12-E15. The B4+
neurons were generated on E13-E16, with a peak around E14.
The overall pattern of neurogenesis of the DRG neurons showed
that the RT97+ neurons were produced prior to the B4+
neurons. These findings are in agreement with earlier
observations that the large DRG neurons are generated earlier
than the small dark neurons. Our findings also suggest the
existence of a third neuronal subpopulation that might be
produced at the latest period of DRG neurogenesis at E15-E16..
0; 59-14-3; 82785-14-6.
221. Kjaerulff, O.; Kiehn, O. Distribution of networks generating and
coordinating locomotor activity in the neonatal rat spinal cord
in vitro: a lesion study. J-Neurosci. 1996 Sep 15; 16(18):
5777-94; ISSN: 0270-6474.
UNITED-STATES. The isolated spinal cord of the newborn rat
contains networks that are able to create a patterned motor
output resembling normal locomotor movements. In this study,
we sought to localize the regions of primary importance for
rhythm and pattern generation using specific mechanical
lesions. We used ventral root recordings to monitor neuronal
activity and tested the ability of various isolated parts of the
caudal thoraciclumbar cord to generate rhythmic bursting in a
combination of 5-HT and NMDA. In addition, pathways
mediating left/right and rostrocaudal burst alternation were
localized. We found that the isolated ventral third of the
spinal cord can generate normally coordinated rhythmic
activity, whereas lateral fragments resulting from sagittal
sections showed little or no rhythmogenic capability compared
with intact control preparations. The ability to generate fast
and regular rhythmic activity decreased in the caudal
direction, but the rhythm-generating network was found to be
distributed over the entire lumbar region and to extend into
the caudal thoracic region. The pathways mediating left/ right
alternation exist primarily in the ventral commissure. As with
the rhythmogenic ability, these pathways were distributed
along the lumbar enlargement. Both lateral and ventral funiculi
were sufficient to coordinate activity in the rostral and
caudal regions. We conclude that the networks organizing
locomotor-related activity in the spinal cord of the newborn
rat are distributed.. 50-67-9; 6384-92-5.
222. Kjaerulff, O.; Kiehn, O. Distribution of networks generating and
coordinating locomotor activity in the neonatal rat spinal cord
in vitro: a lesion study. J-Neurosci. 1996 Sep 15; 16(18):
5777-94; ISSN: 0270-6474.
UNITED-STATES. The isolated spinal cord of the newborn rat
contains networks that are able to create a patterned motor
output resembling normal locomotor movements. In this study,
we sought to localize the regions of primary importance for
rhythm and pattern generation using specific mechanical
lesions. We used ventral root recordings to monitor neuronal
activity and tested the ability of various isolated parts of the
caudal thoraciclumbar cord to generate rhythmic bursting in a
combination of 5-HT and NMDA. In addition, pathways
mediating left/right and rostrocaudal burst alternation were
localized. We found that the isolated ventral third of the
spinal cord can generate normally coordinated rhythmic
activity, whereas lateral fragments resulting from sagittal
sections showed little or no rhythmogenic capability compared
with intact control preparations. The ability to generate fast
and regular rhythmic activity decreased in the caudal
direction, but the rhythm-generating network was found to be
distributed over the entire lumbar region and to extend into
the caudal thoracic region. The pathways mediating left/ right
alternation exist primarily in the ventral commissure. As with
the rhythmogenic ability, these pathways were distributed
along the lumbar enlargement. Both lateral and ventral funiculi
were sufficient to coordinate activity in the rostral and
caudal regions. We conclude that the networks organizing
locomotor-related activity in the spinal cord of the newborn
rat are distributed.. 50-67-9; 6384-92-5.
223. Klinger, W.; Karge, E.; Danz, M.; Krug, M. Nerval influences on liver
cytochrome P450. Exp-Toxicol-Pathol. 1995 Sep; 47(4): 299-
304; ISSN: 0940-2993.
GERMANY. In male young adult Wistar rats the influences of
nucleus raphe electrocoagulation, spinal cord dissection
(cordotomy between C7 and Th1), vagotomy and denervation of
liver hilus by phenol on liver cytochrome P450-system
(cytochrome P450 concentration, ethylmorphine N-
demethylation and ethoxycoumarin O-deethylation activities,
hexobarbitone sleeping time) were investigated. In general the
influences were small or negligible when compared with sham
operated controls, only after vagotomy the depressing effect
of sham operation was abolished. In all cases sham operation
had a depressing effect until up to five weeks after operation..
EC 1.14.13.-; EC 1.5.3.-; 9035-51-2.
224. Klinger, W.; Karge, E.; Danz, M.; Krug, M. Nerval influences on liver
cytochrome P450. Exp-Toxicol-Pathol. 1995 Sep; 47(4): 299-
304; ISSN: 0940-2993.
GERMANY. In male young adult Wistar rats the influences of
nucleus raphe electrocoagulation, spinal cord dissection
(cordotomy between C7 and Th1), vagotomy and denervation of
liver hilus by phenol on liver cytochrome P450-system
(cytochrome P450 concentration, ethylmorphine N-
demethylation and ethoxycoumarin O-deethylation activities,
hexobarbitone sleeping time) were investigated. In general the
influences were small or negligible when compared with sham
operated controls, only after vagotomy the depressing effect
of sham operation was abolished. In all cases sham operation
had a depressing effect until up to five weeks after operation..
EC 1.14.13.-; EC 1.5.3.-; 9035-51-2.
225. Kochs, E. Monitoring of the central nervous system. Acta-
Anaesthesiol-Scand-Suppl. 1996; 109: 60-1; ISSN: 0515-2720.
DENMARK.
226. Kochs, E. Monitoring of the central nervous system. Acta-
Anaesthesiol-Scand-Suppl. 1996; 109: 60-1; ISSN: 0515-2720.
DENMARK.
227. Koerber, H. R.; Mirnics, K. Plasticity of dorsal horn cell receptive
fields after peripheral nerve regeneration. J-Neurophysiol.
1996 Jun; 75(6): 2255-67; ISSN: 0022-3077.
UNITED-STATES. 1. The tibial and sural nerves were
transected and repaired in nine adult cats. The receptive field
(RF) properties of dorsal horn neurons were examined at three
different intervals (5-6, 9, or 12 mo) after axotomy. The
properties examined included RF location, area, and modality
convergence. In some cases, discrete areas of the cell's RF
were stimulated electrically while the evoked cord dorsum
potentials (CDPs) and any intracellularly recorded responses
were simultaneously recorded. 2. At the shortest interval
following reinnervation, the somatotopic organization in the
affected areas of the dorsal horn was lost. Dorsal horn cells
that received input primarily from regenerated fibers had
large, low-threshold excitatory RFs that contained much of the
reinnervated skin. Those cells with RFs restricted to a
fraction of the reinnervated skin had significant components
of their RFs on the foot dorsum supplied by intact fibers (i.e.,
superficial peroneal nerve). 3. At longer intervals the
somatotopic organization remained scrambled. Dorsal horn cell
low-threshold RFs were significantly reduced in size. Many
cells exhibited large areas of excitatory subliminal fringe and
concise inhibitory RFs. In addition, those cells that responded
to peripheral stimuli across a wide range of stimulus
intensities (wide-dynamic-range cells) also exhibited
plasticity in the relative sizes of their low- and high-
threshold RFs. 4. At the shortest recovery time, focal
electrical stimulation of the skin within the RF of an impaled
cell and simultaneous recordings of the evoked CDPs and
postsynaptic potentials revealed that at numerous locations
within the initial large RFs, single fibers or small groups of
fibers could be electrically activated that were not connected
to the dorsal horn cell. At the longer recovery times there was
a much higher incidence of connectivity. 5. These results
suggest that mechanisms affecting both synaptic efficacy of
afferent fiber connections and/or the establishment of
afferent-driven inhibitory inputs may effect the reshaping of
dorsal horn cell RFs after reinnervation. These results are
discussed in relation to their potential contribution to
previously observed cortical plasticity and functional recovery
following similar lesions.
228. Koerber, H. R.; Mirnics, K. Plasticity of dorsal horn cell receptive
fields after peripheral nerve regeneration. J-Neurophysiol.
1996 Jun; 75(6): 2255-67; ISSN: 0022-3077.
UNITED-STATES. 1. The tibial and sural nerves were
transected and repaired in nine adult cats. The receptive field
(RF) properties of dorsal horn neurons were examined at three
different intervals (5-6, 9, or 12 mo) after axotomy. The
properties examined included RF location, area, and modality
convergence. In some cases, discrete areas of the cell's RF
were stimulated electrically while the evoked cord dorsum
potentials (CDPs) and any intracellularly recorded responses
were simultaneously recorded. 2. At the shortest interval
following reinnervation, the somatotopic organization in the
affected areas of the dorsal horn was lost. Dorsal horn cells
that received input primarily from regenerated fibers had
large, low-threshold excitatory RFs that contained much of the
reinnervated skin. Those cells with RFs restricted to a
fraction of the reinnervated skin had significant components
of their RFs on the foot dorsum supplied by intact fibers (i.e.,
superficial peroneal nerve). 3. At longer intervals the
somatotopic organization remained scrambled. Dorsal horn cell
low-threshold RFs were significantly reduced in size. Many
cells exhibited large areas of excitatory subliminal fringe and
concise inhibitory RFs. In addition, those cells that responded
to peripheral stimuli across a wide range of stimulus
intensities (wide-dynamic-range cells) also exhibited
plasticity in the relative sizes of their low- and high-
threshold RFs. 4. At the shortest recovery time, focal
electrical stimulation of the skin within the RF of an impaled
cell and simultaneous recordings of the evoked CDPs and
postsynaptic potentials revealed that at numerous locations
within the initial large RFs, single fibers or small groups of
fibers could be electrically activated that were not connected
to the dorsal horn cell. At the longer recovery times there was
a much higher incidence of connectivity. 5. These results
suggest that mechanisms affecting both synaptic efficacy of
afferent fiber connections and/or the establishment of
afferent-driven inhibitory inputs may effect the reshaping of
dorsal horn cell RFs after reinnervation. These results are
discussed in relation to their potential contribution to
previously observed cortical plasticity and functional recovery
following similar lesions.
229. Kolhekar, R.; Gebhart, G. F. Modulation of spinal visceral
nociceptive transmission by NMDA receptor activation in the
rat. J-Neurophysiol. 1996 Jun; 75(6): 2344-53; ISSN: 0022-
3077.
UNITED-STATES. 1. Thirty-three neurons in the L6-Sl spinal
cord of 30 adult male Sprague-Dawley rats were characterized
for responses to colorectal distention (CRD, 20-80 mmHg, 20
s) and convergent cutaneous receptive fields in the presence
and absence of N-methyl-D-aspartate (NMDA; 1 microM) or D-
serine (1 microM) administered locally by pressure ejection. 2.
NMDA ejected locally increased the resting (spontaneous)
activity, responses to CRD, postdistention afterdischarges,
encoding of visceral nociception, and the size of convergent
cutaneous receptive fields of some neurons. Facilitation of
responses to noxious intensities of CRD (> or = 40 mmHg) was
apparent between 30 s and 4 min after drug ejection. The slope
of stimulus-response functions to graded intensities of CRD
was increased significantly by NMDA, although mean response
threshold was not significantly altered after NMDA ejection. 3.
Facilitatory effects of NMDA on responses to CRD and
increases in size of convergent cutaneous receptive fields
were blocked or reversed by administration of the NMDA
receptor antagonist, 5-amino-2-phosphono-valeric acid. 4. D-
serine, an agonist at the glycine modulatory site on the NMDA
receptor complex, generally mimicked the effects of NMDA on
neurons responsive to CRD. The effects of D-serine were
blocked by the glycine site antagonist 7-chloro-kynurenic acid
(7-CK). 7-CK also blocked NMDA-produced effects on responses
to CRD and increases in size of cutaneous receptive fields. 5.
No differences were found between spinal neurons with and
without documented long ascending projections with respect
to effects of NMDA or D-serine. 6. These findings demonstrate
involvement of spinal NMDA receptors in mediating
hyperexcitability of spinal neurons to visceral nociceptive
input and suggest an important contribution of spinal NMDA
receptors in visceral hyperalgesic syndromes.. 0; 0; 0; 18000-
24-3; 492-27-3; 56-45-1; 6384-92-5; 76726-92-6.
230. Kolhekar, R.; Gebhart, G. F. Modulation of spinal visceral
nociceptive transmission by NMDA receptor activation in the
rat. J-Neurophysiol. 1996 Jun; 75(6): 2344-53; ISSN: 0022-
3077.
UNITED-STATES. 1. Thirty-three neurons in the L6-Sl spinal
cord of 30 adult male Sprague-Dawley rats were characterized
for responses to colorectal distention (CRD, 20-80 mmHg, 20
s) and convergent cutaneous receptive fields in the presence
and absence of N-methyl-D-aspartate (NMDA; 1 microM) or D-
serine (1 microM) administered locally by pressure ejection. 2.
NMDA ejected locally increased the resting (spontaneous)
activity, responses to CRD, postdistention afterdischarges,
encoding of visceral nociception, and the size of convergent
cutaneous receptive fields of some neurons. Facilitation of
responses to noxious intensities of CRD (> or = 40 mmHg) was
apparent between 30 s and 4 min after drug ejection. The slope
of stimulus-response functions to graded intensities of CRD
was increased significantly by NMDA, although mean response
threshold was not significantly altered after NMDA ejection. 3.
Facilitatory effects of NMDA on responses to CRD and
increases in size of convergent cutaneous receptive fields
were blocked or reversed by administration of the NMDA
receptor antagonist, 5-amino-2-phosphono-valeric acid. 4. D-
serine, an agonist at the glycine modulatory site on the NMDA
receptor complex, generally mimicked the effects of NMDA on
neurons responsive to CRD. The effects of D-serine were
blocked by the glycine site antagonist 7-chloro-kynurenic acid
(7-CK). 7-CK also blocked NMDA-produced effects on responses
to CRD and increases in size of cutaneous receptive fields. 5.
No differences were found between spinal neurons with and
without documented long ascending projections with respect
to effects of NMDA or D-serine. 6. These findings demonstrate
involvement of spinal NMDA receptors in mediating
hyperexcitability of spinal neurons to visceral nociceptive
input and suggest an important contribution of spinal NMDA
receptors in visceral hyperalgesic syndromes.. 0; 0; 0; 18000-
24-3; 492-27-3; 56-45-1; 6384-92-5; 76726-92-6.
231. Korade, Z.; Frank, E. Restriction in cell fates of developing spinal
cord cells transplanted to neural crest pathways. J-Neurosci.
1996 Dec 1; 16(23): 7638-48; ISSN: 0270-6474.
UNITED-STATES. At early neural tube stages, individual stem
cells can generate neural crest cells as well as dorsal or
ventral spinal cord cells. To determine whether this
pluripotency is lost as development proceeds, we back-
transplanted quail spinal cells from different developmental
stages and different spinal locations into the crest migratory
pathways of st 16-20 chicken host embryos. The transplanted
spinal cells from st 27 dorsal cord and st 18 ventral cord
differentiated within the new crest environment into sensory
and sympathetic neurons, satellite and Schwann cells, and
melanocytes. St 27 ventral cells still generated several crest
derivatives but not sensory or sympathetic neurons. This loss
in ability to produce neurons correlates with the end of
neurogenesis in ventral cord. The end of neurogenesis in the
cord, therefore, results from an intrinsic change in the
potential of spinal neuroepithelial cells to generate neurons.
232. Korade, Z.; Frank, E. Restriction in cell fates of developing spinal
cord cells transplanted to neural crest pathways. J-Neurosci.
1996 Dec 1; 16(23): 7638-48; ISSN: 0270-6474.
UNITED-STATES. At early neural tube stages, individual stem
cells can generate neural crest cells as well as dorsal or
ventral spinal cord cells. To determine whether this
pluripotency is lost as development proceeds, we back-
transplanted quail spinal cells from different developmental
stages and different spinal locations into the crest migratory
pathways of st 16-20 chicken host embryos. The transpla