The R(-)-enantiomer of efonidipine blocks T-type but not L-type calcium current in guinea pig ventricular myocardium

Abstract

In guinea pig ventricular cardiomyocytes, the R(-)-enantiomer of efonidipine concentration-dependently blocked T-type Ca2+ current with 85% inhibition at 1 microM. In contrast, R(-)-efonidipine (1 microM) had no effect on the L-type Ca2+ current and Ca2+ transient in cardiomyocytes and contractile force in papillary muscles. Thus, R(-)-efonidipine is a highly selective blocker of the T-type Ca2+ current in native myocardia.