| Project/Area Number |
20791355
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | Kyushu University |
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Principal Investigator |
MURATA Yoshihiro Kyushu University, 教育研究部・医療学系, 助教 (40377031)
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| Project Period (FY) |
2008 – 2009
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| Project Status |
Completed (Fiscal Year 2009)
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| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2009: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2008: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 味細胞 / 活動電位 / シナプス / 神経伝達物質 / ATP / ヘミチャネル |
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| Research Abstract |
Subsets of taste bud cells generate action potentials in response to sapid stimuli. Type II taste cells have many taste transduction molecules but lack well elaborated synapses, which leads to the question in the functional significance of action potentials in these cells. We examined the dependence of adenosine triphosphate (ATP) transmitter release from taste cells upon action potentials. To identify Type TT taste cells we used mice expressing a green fluorescence protein (GFP) transgene from the gustducin promoter. Action potentials were recorded by an electrode basolaterally attached to a. single GFP-positive taste cell. ATP release was monitored from gustducin-expressing taste cells by collecting the electrode solution immediately after tastant-stimulated action potentials and using a. luciferase assay to quantify ATP. Stimulation of gustducin-expressing taste cells with a. sweet, bitter, or umami compound on the apical membrane increased ATP levels in the electrode solution; the amount of ATP depended on the firing rate. Increased spontaneous firing rates also induced ATP release from gustducin-expressing taste cells. ATP release from gustducin-expressing taste cells was depressed by tetrodotoxin and inhibited below the detection limit by carbenoxolone. Our data support the hypothesis that action potentials in Type II taste cells enhance ATP release through hemichannels.
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