[Relation between the passive transport of calcium into vesicles of the myocardial sarcolemma and membrane potential].
The effect of membrane potential on the passive 45Ca2+ uptake by cardial sarcolemmal vesicles was investigated. Membrane potentials were generated by the K+ gradient in the presence of valinomycin and were measured using fluorescent dye diS-C3-(5). It was shown that the 45Ca2+ influx into vesicles increased twice after membrane depolarization. Evaluation of the 45Ca2+ influx over a wide range of membrane potentials produced a profile similar to that of current-voltage relationships for single calcium channels in isolated cardiomyocytes. Passive 45Ca2+ transport was inhibited by 1 mM Cd2+ and Co2+. It is suggested that the voltage-dependent Ca2+ influx into vesicles occurs through Ca2+-channels.
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D012508:Sarcolemma / Q000378:metabolism* / Q000502:physiology; D013552:Swine; D014634:Valinomycin / Q000494:pharmacology
D007473:Ion Channels; D014634:Valinomycin; D011188:Potassium; D002118:Calcium
Zavisimost' passivnogo transporta kal'tsiia v vezikuly sarkolemmy miokarda ot membrannogo potentsiala.