Inhibition by ranolazine. (A) Current-voltage relationships before (●) and after (○) the extracellular application of 200 µM ranolazine are shown. 100-ms depolarizing pulses from −100 to 100 mV with 10-mV increments at 0.1 Hz were performed before and after the drug application. n = 3. (B) The potency of current inhibition was the highest with ranolazine, with an IC50 of ∼60 µM. Representative traces are shown in the bottom inset. The dashed line indicates the zero current level. The top inset represents a chemical structure of ranolazine. (C) The diary plot of 200 µM ranolazine was constructed as described in Fig. 2 C. Representative current traces are shown with the zero current lines (dotted lines). (B and C) n = 4. Bar, 500 ms. (D) Effects on the conductance-voltage curve before (●) and after (○) the 200 µM ranolazine exposure. A significant left shift in the SSI curve was observed before (■) and after (□) the 200 µM ranolazine application. Error bars represent SEM.
