| Project/Area Number |
61480384
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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 |
Functional basic dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
NAKAMURA Yoshio Tokyo Medical and Dental University,Professor, 歯学部, 教授 (10010026)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Trigeminal sensory nucleus / Natural stimulation / Low threshold mechanoreceptor / Lateral Inhibition Descending inhibition / Intracellular recording / Inhibitory postsynaptic potential / 抑制性シナプス後電位 / ネコ / 三叉神経感覚核 / 皮質性抑制 |
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| Research Abstract |
Intracellular responses of neurons in the trigeminal spinal nucleus oralis were studied to electrical stimulation of the trigeminal sensory branches and cerebral cortex as well as mechanical stimulation of the oro-facial region in chloralose-anesthetized cats.All the secondary neurone recorded from the spinal nucleus were low threshold mechanorceptive neurons.They were classified into two groups based on the response patterns to electrical stimulation of the trigeminal sensory branches:one showed an excitatory response followed by an IPSP(Type I),and the other only an excitatory response (TypeII).All the neurons projecting to the contralateral thelamic ventral posteromedial nucleus belonged to Type I.The excitatory receptive field of Type I neurons was surrounded by an inhiditory one.An IPSP was also evoked in them by stimulation of the excitatory receptive field following an excitatory response.The spike firing frequency of Type I neurons tended to show a positive correlation with the velocity of application of pressure to the facial skin; in contrast,that of Type IIneurons did so with the amplitude of skin indentation.An IPSP was also evoked in about a half of Type I neurons by stimulation of the facial region of the somatosensory cortex.The latency and duration of IPSPs evoked in Type I neurons by electrical stimulation of trigeminal sensory branches and cortex were much shorter than those of the primary afferent depolarization evoked in the trigeminal spinal nucleus by the preiphral and cortical stimulations. We conclude that the IPSP evoked by the peripheral stimulation is involved in the surround or lateral inhibition in the trigeminal spinal nucleus and that the cortically-as well as peripherally-evoked postsynaptic inhibition of trigeminal sensory neurons plays an improtant role in the early phase of the descending and afferent inhibition of the information transmission in the trigeminal sensory nucleus.
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