1991 Fiscal Year Final Research Report Summary
Examination of the shell theory of nociception
| Project/Area Number |
01480123
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurophysiology and muscle physiology
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| Research Institution | Shiga University of Medical Science |
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Principal Investigator |
YOKOTA Toshikatsu Department of Physiology Shiga University of Medical Science, Professor, 医学部, 教授 (10001752)
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| Co-Investigator(Kenkyū-buntansha) |
KOYAMA Natsu Department of Physiology Shiga University of Medical Science, Assistant, 医学部, 助手 (50135464)
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| Project Period (FY) |
1989 – 1991
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| Keywords | shell theory / ventrobasal complex / nociceptive specific neuron / wide dynamic range neuron / visceral pain / periaqueductal gray / ascending inhibition / thalamus |
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| Research Abstract |
We have proposed the shell theory of thalamic nociception ; NS neurons in the lamina I of the spinal cord and its trigeminal homologue relay peripheral nociceptive input to NS neurons in the shell region of the VB complex. Similarly WDR neurons in the dorsal horn of the spinal cord and its trigeminal homologue relay peripheral input to WDR neurons in the shell region of the VB complex. These two classes of nociceptive neurons constitute a thalamic link in the pain pathway from both the dorsal horn of the spinal cord and its trigeminal homologue, to the somatosensory cortex S, , subserving sensory-discriminative aspect of pain. The proposal was confirmed using the intracellular HRP injection technique in the cat. In the Japanese macaque, both NS and WDR neurons were found in the shell region of theVB complex. These two classes of nociceptive neurons were spatially segregated. Thus, the shell theory was confirmed. The cat thalamus was explored for neurons driven by visceral input from sympathetic nerves. Neurons receiving sympathetic visceral afferent input were found in the population of NS and WDR neurons in the shell region of the caudal VPL. Visceral and cutneous pain pathways share a common projection locus in the VPL.
Inhibitory mechanism acting upon synaptic transmission in nociceptive neurons within the shell region of the VPL was studied in cats. Responses elicited from NS and WDR neurons by electrical stimulation of the inferior cardiac nerve were inhibited following electrical stimulation of either the nucleus raphe dorsalis (NRD) or the ventromedial part of the periaqueductal grey (PAG). The inhibition was found to be partially mediated by an ascending pathway in addition to the well known descending spinal pathways in the dorsolateral funiculi of the spinal cord.
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[Publications] Yokota, T., Koyama, N., Nishikawa, Y., Nishikawa, N., Hasegawa, A. and Fujino, Y.: "Trigeminal nociceptive neurons in the subnucleus reticularis ventralis. I. Response properties and afferent connections." Neuroscience Research. 11. 1-17 (1991)
Description
「研究成果報告書概要(欧文)」より
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