[A study of the antiarrhythmic mechanism of berberine on delayed activation potassium current by voltage clamp].

The effects of berberine (0.1-10 mg/L) on delayed activation potassium current (iK) of canine Purkinje fibers were studied with two-microelectrode voltage clamp technique. Berberine (Ber) significantly reduced the amplitude of iK in concentration-dependent manner. When perfused with 10 mg/L Ber, the amplitude of tail current of the Purkinje fibers decreased immediately and the inhibition rate was 73.6 +/- 4.5% (n = 9, P < 0.001). The inhibition effect of berberine on iK may explain its prolongation effect on action potential duration and its antiarrhythmic action.