1991 Fiscal Year Final Research Report Summary
Coding of gustatory information in the NTS from the soft palate.
| Project/Area Number |
02807170
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Kahoshima University |
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Principal Investigator |
HARADA Shuitsu Kagoshima Univ. Dent. Sch., Instructor, 歯学部, 助手 (60128452)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Taste / Rat / Hamster / GSP / CT / Amiloride / NTS / Sucrose |
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| Research Abstract |
The greater superficial petrosal(GSP)nerve innervates taste buds on the soft palate and project to nucleus tractus solitarius(NTS)in mammals. Electrophysiological recordings from the rat's GSP revealed that the GSP produces robust responses to sweet substances. Behavioral experiment in the rat showed that sectioning of the GSP and/or the chorda tympani(CT)resulted in significant decrease of sucrose solution intake. However, the GSP is only investigated in the rat and is still remained unclear. In this experiment, functions of the GSP were studied in the hamster and the rat neurophysiologically and behaviorally. Neural recordings revealed that the hamster GSP also produces robust responses to various sugars. In the rat, the GSP showed considerably sensitivity to sucrose while the CT was more sensitive to NaCl. And the GSP showed almost no sensitivity to amiloride while response to Na^+ in the CT was depressed by amiloride. Effects of bilateral sectionings of the GSP and/or CT on discriminating sucrose taste were examined through conditioned taste aversion paradigm in the hamster. The degree of the aversion was significantly decreased when the. GSP and/or CT were sectioned bilaterally. The order of the sectioning effects were GSP+CT>GSP>= CT>sham. These results suggest that gustatory information pasted through the GSP to the NTS is important for the discrimination of sweet substances and for the coding mechanisms in the NTS. More experiments in the NTS are necessary to clarify the gustatory coding mechanisms considering the GSP function.
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