| Project/Area Number |
09832001
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
咀嚼
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
NOZAKI Shuichi Tokyo Medical and Dental University Neurobiology, Dentistry, Professor, 歯学研究科, 教授 (90114777)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | masication / CMA / feeding center / Zona Inserta / 咀嚼リズム / 中脳網様体 / HRP |
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| Research Abstract |
Twelve guinea pigs anesthetized with ketamine were used to investigate the origin projecting to mesencephalic masticatory area (MMA) and the pathway from MMA to the cortically induced masticatory rhythm generator (MRG) in the oral part of the gigantocellular reticular formation (GCo). We obtained following results. 1) It was confirmed that two types of rhythmical waxing and waning digastric EMG composed of the bursts fixed and non-fixed with each pulses of repetitive stimulation in MMA.2) HRP labeled neurons were distributed in the ipsilateral zona incerta (Zi) and scattered in the hypothalamus including the lateral hypothalamus area (LHA). 3) Orthodromic field potentials with monosynaptic latency were evoked in MMA by a single stimulation in Zi and LHA.4) Antidromic field potential was evoked in MMA by a single stimulation in MRG.It was suggested that MMA projected from Zi and LHA accepting the trigeminal and autonomic input respectively contributed to the masticatory control.
The feeling for hunger are brought by low blood sugar level or empty stomach and developing the feeding behavior controlled by feeding center in hypothalamus. The mastication owe to a important role of the processing a food ingestion. It was studied effects of stretching the stomach wall and fluctuating the blood sugar level for induced rhythmical mastication in ketamine anesthetized guinea pigs. The threshold of the evoked EMG in right and left digastric muscle for 3 shocks of electrical stimulation in the cortical masticatory area (CMA) was increased by injecting 10% sugar in physiological saline from external jugular vein and decreased by injecting a insulin in abdominal. Strech the wall by injecting hot water at 35ﾟC to the plastic balloon inserted in the stomach was incraesed the threshold of the EMG response. From these result, the masticatory rhythm generator in the bulbar reticular formation will be modulated by the blood suga9r level and stretch of stomach wall.
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