title: Inhibition of Ca(2+)-dependent catecholamine release by myosin light chain kinase inhibitor, wortmannin, in adrenal chromaffin cells.
abstract: To elucidate the possible involvement of myosin light chain kinase (MLCK) in the mechanism of exocytosis, we studied effects of MLCK inhibitor, wortmannin, on the secretory function of bovine adrenal chromaffin cells. Preincubation of chromaffin cells with wortmannin inhibited both acetylcholine- and high K(+)-evoked catecholamine (CA) release. The IC50 for high K(+)-evoked CA release was 1 microM. When the cells were permeabilized with digitonin after wortmannin preincubation, Ca(2+)-dependent exocytosis was inhibited in a dose-dependent manner (IC50, 1 microM). These findings suggest the implication of MLCK in the Ca(2+)-triggered process in the machinery of exocytosis.
authors.affiliation: Life Science Institute, Sophia University, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ohara-Imaizumi
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.forename: S
authors.initials: S
authors.lastname: Nakanishi
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda
authors.forename: S
authors.initials: S
authors.lastname: Muramatsu
authors.forename: Y
authors.initials: Y
authors.lastname: Nonomura
authors.forename: K
authors.initials: K
authors.lastname: Kumakura
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000730:Androstadienes / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D002395:Catecholamines / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D005089:Exocytosis / Q000187:drug effects; D007700:Kinetics; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors*; D011188:Potassium / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D000893:Anti-Inflammatory Agents; D002395:Catecholamines; D009219:Myosin-Light-Chain Kinase; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium; D000077191:Wortmannin