| Project/Area Number |
06454144
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KASAI Haruo Dept.physiol., Facult.Med., Univ.Tokyo, Associate Professor, 医学部・第一生理, 助教授 (60224375)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1995: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1994: ¥4,100,000 (Direct Cost: ¥4,100,000)
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| Keywords | Calcium / Exocrine gland / Exocytosis / Patch Clamp / Zymogeu granule / Acetylcholine / Caged compounds / カルシウム(Ca) / 外分泌腺 / イオンチャネル |
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| Research Abstract |
Agonists evoke Ca^<2+> gradients and oscillations initiating at the trigger zone in exocrine acinar cells. Using a low affinity Ca^<2+> indicator dye, BTC,we found that agonists raised Ca^<2+> concentration as high as 10 muM at the trigger zone. Comparison with the results obtained with fura-2 suggests profuse Ca^<2+> release and Ca^<2+> domains at the trigger zone. The resulting micromolar Ca^<2+> gradients were necessary and sufficient for exocytosis of zymogen granules investigated with the capacitance measurement. In contrast, submicromolar Ca^<2+> gradients selectively gave rise to sequential activation of luminal and basal ion channels. These results emphasize critical role of the micromolar Ca^<2+> gradients in exocytosis, and prompt reinvestigation of other cells using low affinity Ca^<2+> indicators.
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