[Potassium contracture of isolated smooth muscle of the coronary artery].
The effect of K+-ions (80-160 mM) upon electrical and contractile activities of circular smooth muscle strips of cattle coronary arteries was studied using a modified sucrose gap technique. A high-potassium solution produced APs followed by stable depolarization (SD) of smooth muscle cells membrane and phasic-tonic contraction of strips. The APs and the contractions were suppressed with Ca-free solution, Mn+2, and verapamil, the level of SD remaining unchanged. Phasic component of the potassium contraction was more resistant against Mn2+, whereas tonic one-against verapamil. The AP- and SD-initiated contractions of the coronary arterial smooth muscle were activated with external Ca2+ entering smooth muscle cells through potential-dependent Ca-channels of two types: the fast inactivating and the slow non-inactivating ones.
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Nikitina
D000818:Animals; D002118:Calcium / Q000502:physiology; D002417:Cattle; D003331:Coronary Vessels / Q000187:drug effects; D066298:In Vitro Techniques; D008345:Manganese / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology*; D014700:Verapamil / Q000494:pharmacology
D008345:Manganese; D014700:Verapamil; D011188:Potassium; D002118:Calcium
Kalievaia kontraktura izolirovannykh gladkikh myshts koronarnykh arteriĭ.