Endothelin dissociates muscle tension from cytosolic Ca2+ in vascular smooth muscle of rat carotid artery.
Endothelin induced rapid increase followed by a decrease in cytosolic Ca2+ [( Ca2+]i) and a slow increase in muscle tension in the vascular smooth muscle strip of rat carotid artery. Thus, the endothelin-induced contraction was smaller, and it became gradually greater than high K-induced contraction at a given [Ca2+]i. In Ca2+-free solution, endothelin induced a transient increase in [Ca2+]i and a sustained contraction. These results suggest that endothelin-induced contraction is due to the increase in [Ca2+]i, the time-dependent change in Ca2+-sensitivity of contractile elements, and the mechanism which is independent of the increment in [Ca2+]i.
Ozaki
H
H
Department of Veterinary Pharmacology, Faculty of Agriculture, University of Tokyo, Japan.
Sato
K
K
Sakata
K
K
Karaki
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002339:Carotid Arteries / Q000187:drug effects / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D016232:Endothelins; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats
D016232:Endothelins; D010455:Peptides; D011188:Potassium; D002118:Calcium