| Project/Area Number |
15209061
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | KYUSHU UNIVERCITY |
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Principal Investigator |
NINOMIYA Yuzo Kyushu University, Graduate School of Dental Sciences, Professor, 大学院歯学研究院, 教授 (50076048)
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| Co-Investigator(Kenkyū-buntansha) |
SHIGEMURA Noriatsu Kyushu University, Graduate School of Dental Sciences, Research associate, 大学院歯学研究院, 助手 (40336079)
三浦 裕仁 独立行政法人 食品総合研究所, 主任研究員 (80353936)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥36,010,000 (Direct Cost: ¥27,700,000、Indirect Cost: ¥8,310,000)
Fiscal Year 2005: ¥7,800,000 (Direct Cost: ¥6,000,000、Indirect Cost: ¥1,800,000)
Fiscal Year 2004: ¥11,180,000 (Direct Cost: ¥8,600,000、Indirect Cost: ¥2,580,000)
Fiscal Year 2003: ¥17,030,000 (Direct Cost: ¥13,100,000、Indirect Cost: ¥3,930,000)
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| Keywords | taste cell responses / taste nerve fiber responses / taste receptor / gustducin / TRPM5 channels / synapse formation / taste information transmission / 味細胞 / 味覚神経情報伝達 / シナプス / スパイク発生味細胞 / 味覚応答 / ホルモン受容体 / ルースパッチ法 / 鼓索神経 / 舌咽神経 / single cell RT-PCR / T1r3-KOマウス / Ggust-KOマウス / TRPM5-KOマウス / シナプス形成関連分子 / 受容体関連分子 |
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| Research Abstract |
The purpose of this study is to investigate molecular basis for taste reception and information transmission. To do this, by developing new approaches and improving methods, we examined 1) molecular expression of taste cells whose responses to various taste stimuli were recorded by loose-patch recording configuration, 2) similarities and differences of response profiles of taste cells generating action potentials with taste nerve fibers, and compared 3) responses in wild type and T1r3-KO and TRPM5-KO mice. The results demonstrated that taste cells responding to sweet substances did not always express sweet-response-related molecules, such as T1R3(receptor) and Ggust (G-protein). There was only less than 5% of taste cells responding to sweet substances that expressed synapse-related molecule, SNAP25. More than' 60% of taste cells generating action potentials responded to only one of the four basic taste stimuli and groupings of taste cells based on their best-stimulus and cluster analysis were similar to those of taste nerve fibers. T1R3-KO and TRPM5-KO mice showed residual responses to sweet substances. TRPM5-KO mice lacked temperature sensitivities in response to sweet substances. These results suggest that there probably exist multiple receptor and transduction systems for sweet taste. Taste cells generating action potentials in response to taste stimuli lacked conventional synapses. However, similarity of response profiles between taste cells with action potentials and taste nerve fibers to four basic taste stimuli indicates that taste information from taste cells generating action potentials transmitted to the nerve without major modification. Thereby, they may transmit taste information to the nerve by the pathway other than conventional synapses. TRPM5 channels act as not only channels responsible for transduction for sweet taste but also temperature sensor which produce temperature enhancement of sweet responses.
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