EFFECTS OF 4-AMINOPYRIDINE ON CALCIUM CURRENTS AND SODIUM CURRENTS IN GUINEA PIG VENTRICULAR MYOCYTES / 药学学报

ABSTRACT

AIM　To investigate the effect of 4-aminopyridine (4-AP) on ion channels of myocytes. METHODS　L-type calcium channel and sodium channel currents were recorded in guinea pig single ventricular myocyte using whole-cell patch-clamp techniques. RESULTS　4-AP, 0.1, 0.5 and 1.0 mmol*L-1 were shown to inhibit L-type calcium channel currents (ICa,L) and sodium channel currents (INa) concentration-dependently. The percentage of inhibition were (11.6±1.7)%, (37.5±8.3)% and (54.5±6.9)% (P<0.01) respectively for ICa,L, and (22.1±14.3)% (P<0.05), (39.4±8.8)% and (62.3±6.8)% (P<0.01) respectively for INa. 4-AP 0.5 mmol*L-1 shifted the I-V curves of ICa,L and INa upwardly. CONCLUSION　4-AP blocked L-type calcium channel and sodium channels in guinea-pig ventricular myocytes concentration-dependently.