Chloride Effiux in Cyclic AMP-Induced Configurational Change of Bovine Pulmonary Artery Endothelial Cells

a variety of other vasoactive agents, calcium ionophore, phorbol ester, or cyclic GMP. The cyclic AMP-induced configurational change was completely inhibited by 2.5 mM N-phenylanthranilic acid or 145 mM sodium gluconate (Clchannel inhibitors) and was partially inhibited by 2.5 mM 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), but it was not affected by deprivation of Ca2' or Na+ ion, 1 mM bumetanide (Clcotransport inhibitor), 1 mM amiloride (Na+/H+ exchange inhibitor), 0.1 mM verapamil (Ca'+ channel inhibitor), or 5 mM BaCI2 (K' channel inhibitor), by change in cellular pH, or by pertussis toxin. Trifluoperazine (calmodulin inhibitor, 50 ,lM), 1 mM EGTA plus 100 ,IM 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester (TMB-8, intracellular Ca2' antagonist), and 5 ,uM cytochalasin B also produced cellular retraction, but these changes were not blocked by chloride channel inhibition. In the presence of 0.1 mM ouabain plus 0.1 mM bumetanide, 36CIuptake was decreased by isoproterenol plus isobutylmethylxanthine while its efflux was enhanced. NPhenylanthranilic acid inhibited the stimulated efflux. We conclude that cyclic AMP induces a configurational change of endothelial cells that is related to Clefflux from the cells; the cellular effects may play a role in vascular function. (Circulation Research 1990;66:957-967)