Figure 4.

Effects of hypericin on I_K currents. (A) Current traces showing effects of 1.0 µM hypericin on whole-cell I_K currents (representative of seven cells). The currents were evoked by voltage steps from −110 to +70 mV in 20 mV increments for 150 ms following a prepulse to −50 mV for 50 ms to inactivate the I_A current. (B) Summary data of the ratio (I/I_o) of the whole-cell I_K current evoked at +30 mV before (I₀) and after (I) application of different concentrations of hypericin. ***P < 0.001, significantly different from control; one-way anova. The steady-state outward I_K current (+30 mV) was measured as mean value in a range from 85% to 95% of the current trace.