Endothelins and membrane potential of vascular smooth muscle of the canine coronary artery.
We investigated the effects of endothelins on the membrane potential of vascular smooth-muscle cells of canine coronary artery, using glass microelectrodes. In tissues with endothelium, endothelin-1 (ET-1), from 10(-12) to 10(-9) M, did not alter the membrane potential. Higher concentrations of the peptide produced sustained depolarization without detectable hyperpolarization. Endothelin-3 (ET-3, 10(-11) to 10(-8) M) did not produce significant membrane hyperpolarization in tissues with endothelium. Prostaglandin F2 alpha (10(-5) M) depolarized the cell membrane by about 6 mV. ET-1 (10(-9) M) did not evoke detectable hyperpolarization in the presence of prostaglandin F2 alpha. In tissues incubated with BQ123 (10(-6) M, a selective ETA-receptor antagonist), which attenuated the depolarization evoked by ET-1, both isopeptides did not produce detectable hyperpolarization. These findings suggest that ET-1 and ET-3 do not evoke the release of endothelium-derived hyperpolarizing factor in the canine coronary artery.
Nakashima
M
M
Center for Experimental Therapeutics, Baylor College of Medicine, Houston, Texas.
Vanhoutte
P M
PM
D000818:Animals; D001685:Biological Factors / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects; D015237:Dinoprost / Q000494:pharmacology; D004285:Dogs; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010456:Peptides, Cyclic / Q000494:pharmacology
D001685:Biological Factors; D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D010456:Peptides, Cyclic; C067410:endothelium-dependent hyperpolarization factor; D015237:Dinoprost; C072247:cyclo(Trp-Asp-Pro-Val-Leu)