2004 Fiscal Year Final Research Report Summary
Synaptic convergence of ATP P2X receptor-sensitive inputs and capsaicin VR1 receptor-sensitive inputs onto spinothalamic tract neurons
| Project/Area Number |
14370474
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Orthopaedic surgery
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| Research Institution | wakayama medical university |
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Principal Investigator |
TANIGUCHI Yasunori wakayama medical university, Depart.of Orthopedic Surg., lecture, 医学部・整形外科, 講師 (10264889)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Munehito wakayama medical university, Depart.of Orthopedic Surg., professor, 医学部・整形外科, 教授 (60201018)
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| Project Period (FY) |
2002 – 2004
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| Keywords | patch clamp recording / synaptic response / spinal cord / slice / spinothalamic tract neuron / ATP receptor / capsaicin receptor / pain sensation |
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| Research Abstract |
The inhibitory system in the spinal cord plays an important role in regulating nociceptive sensory inputs. We found inhibitory synaptic activity in lamina V neurons of the spinal dorsal horn following the activation of capsaicin TRPV1 receptors. Experiments were performed with spinal cord slice preparations and inhibitory postsynaptic currents(IPSCs) were recorded using whole-cell patch-clamp technique. Bath application of capsaicin increased the amplitude and frequency of GABAergic and glycinergic spontaneous IPSCs (sIPSCs) in the majority of lamina V neurons tested. Repetitive electric stimulation of C primary afferents also induced facilitation of sIPSCs in the majority of lamina V neurons. When CNQX and APV were used to block glutamatergic synaptic transmission, the effects of capsaicin were not abolished. The effects of capsaicin were completely blocked in the presence of tetrodotoxin. Furthermore, capsaicin induce facilitation of sIPSCs was significantly reduced in the presence of several antagonists of substance P receptors. These results indicated that the release of substance P from capsaicin-sensitive C-primary afferents may activate GABAergic and glycinergic interneurons in superficial laminae, and the inhibitory activity may be further forwarded to lamina V neurons. The capsaicin-sensitive inhibitory pathway may play an important role in the control of nociceptive transmission in the spinal cord.
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Research Products
(14 results)
