title: [Relation of Ca2+ efflux from the heart to the concentration of Ca-channel blockers].
abstract: Dependence of calcium ion efflux from the heart ventricles on the concentration of verapamil, fenigidine and nicardipine was studied in frogs, using Ca-sensitive electrodes. The effect of sodium and potassium ions was also investigated. It was established that dependence of calcium ion efflux (delta Ca2+) on the concentration of Ca-antagonists (B) may be expressed by the following formula: (Formula: see text). With cellular membrane depolarization 50 mM KCl, none of the blockers (10(-5) M) caused Ca2+ efflux from ventricular cells. Analogous phenomenon was noted in low-sodium solution (60 mM).
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism*; D009529:Nicardipine; D009543:Nifedipine / Q000031:analogs & derivatives / Q000494:pharmacology; D011895:Rana ridibunda; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D014700:Verapamil; D009529:Nicardipine; D009543:Nifedipine; D002118:Calcium
vernacular_title: Zavisimost' vykhoda Ca2+ iz serdtsa ot kontsentratsii blokatorov Ca-kanalov.