Fig. 3. Concentration–response curves for resting and inactivated sodium channels. The pulse protocol is shown in the inset. The resting affinity for prenylamine in GH3sodium channel was measured with a prepulse of −150 mV for 10 s, and the inactivated affinity was measured with a prepulse of −60 mV for 10 s. The peak amplitudes of Na+currents, evoked by a test pulse to +30 mV for 4.4 s, were measured at various drug concentrations, normalized with respect to the peak amplitude in control, and plotted against the drug concentration. Data are reported as the mean ± SE (n = 6 for all groups). Solid lines represent fits to the data with the Hill equation.