1990 Fiscal Year Final Research Report Summary
Functional Roles of Neuropeptides in The Cortical Taste Area
| Project/Area Number |
01571013
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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 | Osaka University |
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Principal Investigator |
YAMAMOTO Takashi Dental School, Associate Professor, 歯学部, 助教授 (60028793)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUO Ryuji Dental School, Assistant Professor, 歯学部, 講師 (30157268)
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| Project Period (FY) |
1989 – 1990
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| Keywords | cerebral cortex / taste / neuropeptide / taste aversion / learning / c-fos protein |
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| Research Abstract |
Neurotensin, cholecystokinin, enkaphalin, neurokinin, and calcitonin-gene related peptide (CGRP) were localized in the cerebral cortex of rats using the immunohistochemical method. Among these neuropeptides tested, only CGRP was found in nerve fibers within the agranular and dysgranular insular regions of the cortical taste area. The retrograde double-staining technique and ibotenic acid micro-lesion method suggest that CGRP-containing cells within or near the thalamic taste area (VPMpc) send axons to the gustatory insular cortex. The levels of insular cortical CGRP were measured with the radio-immuno-assay method following intraoral stimulation with various taste stimuli. The CGRP levels in the gustatory part of the insular cortex were increased significantly by strongly aversive taste stimuli such as quinine hydrochloride and conditioned taste stimuli (NaCl or sucrose) which animals had been taught to avoid. These results suggest that CGRP in the gustatory insular cortex is concerned with rejection or avoidance behaviors to aversive taste stimuli. One of the oncogene proteins, c-fos protein, was produced markedly within the cortical taste area after establishment of conditioned taste aversion learning. Although the function of this protein still remains to be solved, it is probable that this protein is concerned with the memory of taste in the cortical taste area which is known to play an important role in acquisition and retention of the conditioned taste aversion.
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