title: Phorbol-stimulated influx of extracellular calcium in rat pulmonary artery endothelial cells.
abstract: Stimulation of rat pulmonary artery endothelial cells (RPAEC) with phorbol 12-myristate 13-acetate (PMA) resulted in an increase in intracellular calcium ([Ca2+]i). Unlike the response to bradykinin, C5a and tumor necrosis factor-alpha (TNF-alpha) previously reported (15), the PMA-induced increase in [Ca2+]i was predominantly dependent on extracellular calcium. The PMA response paralleled the BAY K 8644-induced, extracellular calcium-dependent increase in [Ca2+]i. Pretreatment of endothelial cells with the protein kinase C inhibitor staurosporine resulted in a concentration-dependent inhibition of the increase in [Ca2+]i in response to PMA. The ability of PMA analogues to induce significant increase in [Ca2+]i paralleled their ability to induce O2- generation in neutrophils. The PMA-induced influx of extracellular Ca2+ was inhibited by the L-channel selective antagonists diltiazem, nifedipine, nicardipine, and verapamil in a dose-dependent manner. Depolarizing conditions induced by high [K+]o enhanced the calcium response to PMA. The data presented are consistent with the hypothesis that PMA-induced increases in [Ca2+]i in endothelial cells are the result of Ca2+ influx through voltage-dependent L-type Ca2+ channels.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor 48109.
authors.forename: H S
authors.initials: HS
authors.lastname: Murphy
authors.forename: M
authors.initials: M
authors.lastname: Maroughi
authors.forename: G O
authors.initials: GO
authors.lastname: Till
authors.forename: P A
authors.initials: PA
authors.lastname: Ward
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D016764:Cell Polarity / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology*
chemical_list: D000470:Alkaloids; D002121:Calcium Channel Blockers; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium; D001920:Bradykinin; D002118:Calcium