| Co-Investigator(Kenkyū-buntansha) |
NAITOH Masayuki Olympus Optical Co., Ltd., Chief Researcher, 第2開発部, 課長(研究職)
TAMURA. Atsushi Faculty of Medicine, Hiroshima University, Assistant Professor, 医学部, 講師 (30261225)
MASUJIMA Tsutomu Faculty of Medicine, Hiroshima University, Professor, 医学部, 教授 (10136054)
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| Research Abstract |
We have developed a new type of laser-spectromicroscope to analyze the dynamics of microorgans in living cells and to clarify the secretary mechanisms of granules which contain hormones and transmitters in living cells. Rat basophilic leukemia cells, which exhibit a calcium-dependent secretion of granules, were observed using a dual focused video-microscope. Our results suggest that increase of intracellular Ca concentration ([Ca]i) is not sufficient for exocytosis stimulated with antigen, but release of Ca from intracellular stores induces Ca-influx, followed by exocytosis in RBL-2H3 cells. Secretion of insulin from pancreatic the β-cells and a mouse insulinoma cells line MIN6 with glucose results in an exocytotic reaction through membrane depolarization and an increase of [Ca]i. To investigate the relationship between membrane depolarization and intracellular calcium mobilization in MIN6 cells, we developed a simultaneous double-probe imaging video-microscope system, which could simultaneously detect two different kinds of fluorescent signals from a single cell. Our results suggest that cyclic adenosine diphosphate-ribose and Inositol 1,4,5-trisphosphate are mediators of calcium release stimulated by glucose and ACh in MIN6 cells, respectively. These methods would be useful not only for investigating the detailed relationship between intracellular signaling mechanisms and intracellular calcium mobilization in MIN6 cells and RBL-2H3 cells, but also for studying the signaling mechanisms in many kinds of cells and for clinical pharmacy.
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