1994 Fiscal Year Final Research Report Summary
Regulation of salivary secretion : dynamic analysis by confocal laser microscopy
| Project/Area Number |
05671514
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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 School of Medicine |
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Principal Investigator |
SEGAWA Akihisa Kitasato University, School of Medicine, Lecturer, 医学部, 講師 (50154638)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Salivary gland / Secretion / Intracellular signaling / Confocal microscopy |
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| Research Abstract |
Rat parotid acinar cells possess two secretory systems regulated by different receptor and signal transduction mechanisms. Stimulation of the beta-adrenoceptor leads to enzyme release by exocytosis via cyclic AMP,while stimulation of alpha-adrenoceptors and muscarinic cholinoceptors triggers fluid secretion mediated by phosphoinositides and calcium. Confocal microscopy of living parotid acinar cells stimulated with the beta-agonist isoproterenol and the muscarinic agonist carbachol have shown two exocytosis mechanisms. 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 use of phorbol ester TPA,Thapsigargin, A23187 and H-7 in conjunction with the F-actin staining has suggested that microfilaments and calcium, but not protein kinase C,are important regulators for the discrimination of these processes.
It was also obeserved that under the secretory phase the tight junctional permeability in acini increase to allow permeation of large molecules through the paracellular pathway with flexible size-selectivity characteristics.
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