| Project/Area Number |
12144209
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Biological Sciences
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| Research Institution | National Institute for Physiological Sciences (2004)
Okazaki National Research Institutes (2000-2003) |
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Principal Investigator |
NEMOTO Tomomi (2004) National Institute for Physiological Sciences, Center for Brain Experiment, Section of Information Processing, Associate Professor, 脳機能計測センター, 助教授 (50291084)
河西 春郎 (2000-2003) 岡崎国立共同研究機構, 生理学研究所, 教授 (60224375)
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| Co-Investigator(Kenkyū-buntansha) |
根本 知己 岡崎国立共同研究機構, 生理学研究所, 助手 (50291084)
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| Project Period (FY) |
2000 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥33,000,000 (Direct Cost: ¥33,000,000)
Fiscal Year 2004: ¥8,200,000 (Direct Cost: ¥8,200,000)
Fiscal Year 2003: ¥8,200,000 (Direct Cost: ¥8,200,000)
Fiscal Year 2002: ¥8,200,000 (Direct Cost: ¥8,200,000)
Fiscal Year 2001: ¥8,400,000 (Direct Cost: ¥8,400,000)
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| Keywords | Physiology / Signal transduction / Two-photon microscope / Exocrine gland / High performance laser / 2光子顕微鏡 / ケージド試薬 / 開口放出 / アクチン / 溶液輸送 / 塩素イオンチャネル / 膵臓外分泌腺 / 急性膵炎 / 2光子励起 / ケイジド試薬 / グルタミン酸受容体 |
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| Research Abstract |
Exocytosis and fluid-secretion in epithelial cells and synaptic functions were studied with two-photon excitation imaging and uncaging of caged-compounds.
1) We have developed functional mapping of Ca^<2+>-activated channels using two-photon uncaging of caged-Ca^<2+> compound, which has an extraordinary spatial resolution because of the Ca^<2+> domain effect caused by caged-Ca^<2+> itself. In mouse pancreatic acinar preparations, we found that Ca^<2+>-activated Cl^- channel distributed both in the apical and basal membranes, but was absent in the lateral membrane. This distribution prevents the reuptake of Cl^- secreted into the lumen to the lateral membrane, and allows effective unidirectional transport of Cl^-from the basal membrane into the lumen. The lack of functional channels or transporters in the lateral membrane might be utilized in other epithelial transports, and supports the push-pull mechanism of fluid secretion in rodent pancreas.
2) We have also developed a new imaging app
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roach to visualize exocytosis in intact tissue based on two-photon imaging of extracellular polar tracer (TEP imaging). TEP imaging revealed the sequential exocytosis in exocrine pancreas, where Ω-shaped profiles of individual vesicles were stably maintained by rapid coating of the vesicles with F-actin. Impairment of F-actin coating resulted in vacuole formation, which is an early sign of acute pancreatitis.
3) We have found that sequential exocytosis also occurred in the guinea pig nasal gland, but with a substantial delay from the onset of fluid secretion.
4) TEP imaging visualized exocytosis of individual insulin vesicles in the intact islets of Langerhans, and suggested that the fusion pore of insulin vesicles is made of lipid from its very beginning.
5) We have developed an optical approach to stimulate neurons with submicron spatial resolution using two-photon uncaging of a caged-glutamate compound. We found that spine-head volumes tightly correlated with glutamate sensitivity, and enlargement of spine head underlay long-term potentiation. Less
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