Fig. 5. Voltage dependence of steady-state inactivation of the Na⁺ currents. (A) The dependence was determined by measuring peak current elicited by a single depolarization to –34 mV from a range of 200 ms conditioning voltages. (B) V_1/2=–79.8 mV, k=8.2 mV for perforated recording (filled circles), V_1/2=–86.3 mV, k=9.4 mV for conventional recording (open circles). (C) V_1//2=–98.4 mV, k=9.6 mV for 0.5 mmol l^-1 GTPS (filled triangles), V_1/2=–86.1 mV, k=10.0 mV for 1 mmol l^–1 GDPßS (open triangles). For comparison, the broken line for conventional recording is plotted in B. The values are means ± S.E.M. obtained from 7–14 cells.