1999 Fiscal Year Final Research Report Summary
Brain mechanisms of taste quality and hedonic processing
| Project/Area Number |
09470401
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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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 Fac. of Human Sci., Osaka Univ., Professor, 人間科学部, 教授 (60028793)
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| Co-Investigator(Kenkyū-buntansha) |
YASOSHIMA Yasunobu Fac. of Human Sci., Osaka Univ., Res. Associate, 人間科学部, 助手 (00273566)
SAKO Noritaka Fac. of Human Sci., Osaka Univ., Res. Associate, 人間科学部, 助手 (90243154)
SIMURA Tsuyoshi Fac. of Human Sci., Osaka Univ., Assistant Professor, 人間科学部, 講師 (80150332)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Taste / Quality / Hedonics / Brain / Behavior / Neuroscience |
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| Research Abstract |
1) To elucidate the involvement of brain areas in conditioned taste aversion (CTA), we studied the induction of immediate-early genes, c-fos and zif268 as markers of neuronal activation. In the CTA conditioning procedure, rats ingested the conditioned stimulus (CS, 0.5 M sucrose) and received an i. p. injection of 0.15 M LiCI (2% of body weight) as the unconditioned stimulus (US). We compared expressions of c-fos-like (c-FLI) and ZIF (ZIR) immunoreactivities in different rats. The number of c-FLI and ZIP positive cells in the supramammillary area (SuM) of those rats re-exposed to the CS was significantly larger than in those to other rats. In the behavioral study, lesions of the SuM before the single CS-US pairing caused no disruption of the acquisition of the aversion but accelerated its extinction. These results suggest that the SuM cell participate in acquisition mechanism of CTA formation.
2) Opioids are suggested to be involved in generation of palatability and facilitation of consumption of food and fluid. We measured the level of an endogenous opioid, β-endorphin, in the cerebrospinal fluid (CFS) and plasma after free drinking of water and taste solutions in Wistar rats. The results suggest that the release of β-endorphin is positively correlated with the palatability of taste stimuli, and that CSF β-endorphin also reflects the reinforcement of fluid intake in thirsty animals.
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