title: [Selective inhibition of the tonic component of portal vein smooth muscle cell potassium contracture by verapamil].
abstract: The studies were performed on the rat portal vein smooth muscle cells, using double sucrose-gap method. 10(-9)--10(-7) M-verapamil was shown to selectively block the tonic component of potassium contracture. Since potassium depolarization of the membrane persists, it may evidence that verapramil had a specific effect on the excitation-contraction coupling by blocking the passive calcium entry into the muscle cells. At higher concentrations (10(-6)--10(-5) M) verapramil produced inhibition of the phasic component of potassium contracture by blocking the potential-dependent calcium canals of the portal vein smooth muscle cell membrane responsible for generation of the action potentials.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011169:Portal Vein; D011188:Potassium / Q000037:antagonists & inhibitors*; D051381:Rats; D014700:Verapamil / Q000494:pharmacology*
chemical_list: D014700:Verapamil; D011188:Potassium
vernacular_title: Selektivnoe tormozhenie verapamilom tonicheskoĭ komponenty kalievoĭ kontraktury gladkomyshechnykh kletok vorotnoĭ veny.