| Project/Area Number |
62480373
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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 |
SHUICHI NOZAKI School of Dentistry, Tokyo Dental and Medical University, 歯学部, 助教授 (90114777)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1987: ¥5,300,000 (Direct Cost: ¥5,300,000)
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| Keywords | Isolated brainstem / Masticatory Rhythm Generator / 椎骨動脈灌流法 / 延髄巨大細胞網様核 / 咀嚼リズムジェネレータ / 若い成熟モルモット / 脳幹摘出標本 / 咀嚼リズム発生器 / モルモット |
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| Research Abstract |
Our previous studies in the ketamine-anesthetized guinea pig have demonstrated that the rhythm generator responsible for induction of the rhythmical jaw movement, by repetitive stimulation of the cortical masticatory area (CMA), is located in the oral portion of the nucleus reticularis gigantocellularis (GCo), which is activated by tonic input from the CMA via neurons in the dorsal part of the nucleus reticularis paragigantocellularis (dPGC) and sends the rhythmical excitatory output to the anterior digastric motoneurons (DMs) via the premotor neurons in the caudal portion of the nucleus reticularis gigantocellularis. In this study we investigated by the intracellular method the input-output properties of neurons in GOo and dPGC, with the following results:
1) Single pulse CMA stimulation evoked EPSPs in dPGC neurons with a latency coincident with the onset of the negative field potential in the dPGC monosynaptically evoked by the same CMA stimulation. Repetitive CMA stimulation did not induce any rhythmical intracellular potential in dPGC neurons.
2) Neurons are found in the GCo that responded to repetitive CMA stimulation with a rhythmical potential, with spike bursts on the depolarizing phase, which coincided with the rhythmical facilitation of simultaneously induced negative field potential in the DM pool.
3) Averaging of the intracellular potential of GCo neurons by spontaneous spikes of dPGC neurons revealed an EPSP after a monosynaptic latency. We conclude that dPGC neurons monosynaptically recieve a tonic excitatory input from the CMA, and supply tonic activating inpulses to GCo neurons during repetitive CMA stimulation to generate a rhythmical activity in these neurons.
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