Fig. 3.
Effects of risperidone (10 μM) on action potential configuration in single canine ventricular myocytes paced a 1 Hz recorded 5 min after the drug superfusion (A). B: Cumulative concentration-dependent effects of risperidone on action potential duration measured at various level of repolarization in canine myocytes (n=5). C: Comparison of the APD prolongation effect of risperidone in canine ventricular myocytes (n=5) and guinea-pig papillary muscles (n=9). The risperidone induced prolongation of APD90 was normalized to control APD90 and expressed as its percent. Solid lines were obtained by fitting the data to the two-state Boltzmann model in order to determine EC50 values.