| Project/Area Number |
11672171
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biological pharmacy
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| Research Institution | Hiroshima University |
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Principal Investigator |
OZAWA Koichiro Faculty of Medicine, Hiroshima University, Professor, 医学部, 教授 (10211822)
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| Co-Investigator(Kenkyū-buntansha) |
OJIMA Noriyuki Falucty of Medicine, Hiroshima University, Research Associate, 医学部, 助手 (20311805)
MASUJIMA Tsutomu Faculty of Medicine, Hiroshima University, Professor, 医学部, 教授 (10136054)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | infrared laser-spectromicroscope / histamine / mast cells / RBL-2H3 cells / exocytosis / pharmacology / clinical pharmacy / ヒスタミン |
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| Research Abstract |
We have developed a new type of infrared laser-spectromicroscope to analyze the dynamics of microorgans in living cells/tissues and to clarify the secretory mechanisms of granules which contain hormones and transmitters in living cells/tissues. Rat basophilic leukemia (RBL-2H3) cells, a tumor analog of rat mucosal mast cells, have been widely used as a model for the study of mechanisms underlying exocytotic process. In this sutdy, simultaneous analysis of exocytosis of histamine-containing secretory granules and concentration of intracellular Ca^<2+> ([Ca^<2+>]i) with light/fluorescence microscope was used to characterize the antigen-induced Ca^<2+> responses and exocytosis of single fluo-3-loaded RBL-2H3 cells in the presence and absence of extracellular Ca^<2+>. When the extracellular Ca^<2+> was absent, exocytosis was not observed, but the level of [Ca^<2+>]i was enough high (i.e.300-400 nM) for secretion of granules at 30 sec after the stimulation with antigen. Although antigen-induced elevation of [Ca^<2+>]i was not observed in the presence of external Ca^<2+> after the pre-treatment of RBL-2H3 cells with thapsigargin to release and deplete Ca^<2+> from the intracellular stores, the cells showed exocytosis of secretory granules. In the presence of extracellular Ca^<2+>, the elevation of [Ca^<2+>]i with thapsigargin was sustained, indicating that release of Ca^<2+> from intracellular stores may induce Ca^<2+>-influx. These results suggest that increase of [Ca^<2+>]i is not sufficient for exocytosis stimulated with antigen, but release of Ca^<2+> from intracellular stores induces Ca^<2+>-influx, followed by exocytosis in RBL-2H3 cells.
These methods would be useful not only for investigating the detailed relationship between intracellular signaling mechanisms and intracellular calcium mobilization in RBL-2H3 cells, but also for studying the signaling mechanisms in many kinds of cells and for clinical pharmacy.
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