title: Effects of hyposmotic stress on exocytosis in isolated turbot, Scophthalmus maximus, hepatocytes.
abstract: The effect of hyposmotic shock on exocytosis was examined in isolated hepatocytes of turbot, a marine flatfish, using the molecular probe FM1-43. Sudden exposure to a reduced osmolality caused an increase in cell exocytic activity related to the osmotic gradient between intra- and extracellular fluids. Cytoskeletal microtubules could contribute to this hyposmotic-induced exocytosis since colchicine inhibited the process. Protein kinase C, phosphatidylinositol-3 kinase, phospholipases A2, C and D could constitute key enzymes in the mechanism since their inhibition by specific agents altered the hyposmotic-induced exocytic activity. Moreover, arachidonic acid and derivates from the 5-lipoxygenase pathway as well as calcium could participate in the process. As regulatory volume decrease (RVD) exhibited by turbot hepatocytes following hyposmotic stimulation involves similar features, a potential role of exocytosis in volume regulation is suggested. In particular, exocytosis could serve RVD by contributing to ATP release since this latter process similarly appeared to be phospholipase D-dependent and related to the osmotic gradient. This study provides the first evidence of a volume-sensitive exocytosis that could aim at volume constancy in a marine teleost fish cell type.
authors.affiliation: Unité de Physiologie Comparée et Intégrative, U.F.R. Sciences et Techniques, 6 Avenue Le Gorgeu CS 93837, 29238 Brest Cedex 3, France. Helene.Ollivier@univ-brest.fr
authors.forename: Hélène
authors.initials: H
authors.lastname: Ollivier
authors.forename: Karine
authors.initials: K
authors.lastname: Pichavant-Rafini
authors.forename: Eneour
authors.initials: E
authors.lastname: Puill-Stephan
authors.forename: Patrick
authors.initials: P
authors.lastname: Calvès
authors.forename: Liliane
authors.initials: L
authors.lastname: Nonnotte
authors.forename: Guy
authors.initials: G
authors.lastname: Nonnotte
mesh_terms: D020001:1-Butanol / Q000494:pharmacology; D000470:Alkaloids; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D053119:Benzophenanthridines; D002462:Cell Membrane / Q000502:physiology; D003078:Colchicine / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D004963:Estrenes / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D005412:Flatfishes / Q000502:physiology*; D005456:Fluorescent Dyes; D022781:Hepatocytes / Q000502:physiology; D007213:Indomethacin / Q000494:pharmacology; D015759:Ionomycin / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D009637:Masoprocol / Q000494:pharmacology; D009997:Osmotic Pressure; D010617:Phenanthridines / Q000494:pharmacology; D011726:Pyridinium Compounds; D011760:Pyrrolidinones / Q000494:pharmacology; D000644:Quaternary Ammonium Compounds; D011796:Quinacrine / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: D000470:Alkaloids; D000730:Androstadienes; D053119:Benzophenanthridines; D004963:Estrenes; C073804:FM1 43; D005456:Fluorescent Dyes; D007546:Isoquinolines; D010617:Phenanthridines; D011726:Pyridinium Compounds; D011760:Pyrrolidinones; D000644:Quaternary Ammonium Compounds; D013449:Sulfonamides; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D003571:Cytochalasin B; D015759:Ionomycin; D019284:Thapsigargin; D009637:Masoprocol; D020001:1-Butanol; C016299:chelerythrine; D011796:Quinacrine; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D003078:Colchicine; D000077191:Wortmannin; D007213:Indomethacin