Effect of inhibitors of slow calcium current on resting calcium efflux from cat papillary muscles.
Examination of influence of divalent cations (Co2+, Ni2+, Mn2+) and organic blockers (verapamil and D600) on calcium efflux from resting mammalian myocardium shows that they either inhibit or increase transiently 45Ca2+ efflux, depending on the site of action. It seems that those agents whose sites of action are limited to the sarcolemma inhibit Ca2+ efflux. Co2+, Ni2+, verapamil and D600 belong to this group. Mn2+ ions which act also apparently on intracellular structures increase transiently Ca2+ efflux. Such a finding illustrates a diversity in mechanisms of action in a group of agents generally classified as calcium channel blockers.
Prokopczuk
A
A
Department of Clinical Physiology, Postgraduate Centre of Medical Education, Warsaw.
Pytkowski
B
B
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D002415:Cats; D004553:Electric Conductivity; D005711:Gallopamil / Q000494:pharmacology; D066298:In Vitro Techniques; D010210:Papillary Muscles / Q000378:metabolism*; D012146:Rest; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D002413:Cations, Divalent; D005711:Gallopamil; D014700:Verapamil; D002118:Calcium