1992 Fiscal Year Final Research Report Summary
Exocytosis in living salivary glands : dynamic analysis by video microscopy and confocal microscopy
| Project/Area Number |
02670814
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Morphological basic dentistry
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| Research Institution | Kitasato University |
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Principal Investigator |
SEGAWA Akihisa Department of Anatomy, Assistant Professor, 医学部, 講師 (50154638)
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| Co-Investigator(Kenkyū-buntansha) |
TERAKAWA Susumu 岡崎国立共同研究機構生理学研究所, 機能協同部門, 助教授 (50014246)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Salivary glands / Exocytosis / Confocal microscopy / Video microscopy / Signal transduction / Cytoskelaton |
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| Research Abstract |
Rat parotid acinar cells possess two distinct secretion systems regulated by different receptor-intracellular signalling mechanisms, i.e., enzyme release mediated by the beta-receptor and fluid secretion triggered by the alpha- and muscarinic receptors. Previous light and electron microscopic observations on fixed cells have shown that the exocytosis caused by the beta-agonist results in the enlargement of luminal membrane and its subsequent reduction by endocytosis, whereas the alpha- and muscarinic agonists induce vacuole formation that might arise from the swelling of a part of Golgi apparatus. The observation of living parotid acinar cells with video-enhanced microscopy and confocal microscopy during stimulation with the beta-agonist isoproterenol and the muscarinic agonist carbachol have shown that, contrary to the previous interpretations, isoproterenol evoked exocytosis involving neither the gross enlargement of luminal membrane nor the light microscopically detectable endocytosis. Both of these membrane events were instead observed in cells stimulated with carbachol ; the "vacuoles" formed in these cells were considered mostly as the enlarged lumina. These results indicate that two distinct exocytosis-endocytosis coupling mechanisms exist in the salivary secretion system. The staining of the stimulated cells for F-actin suggested the possible involvement of microfilaments and calcium in the discrimination of these different membrane dynamics.
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