Figure 8. Effects of CvIV4 on activation and inactivation of Na_v1.2, Na_v1.3, Na_v1.4 and Na_v1.5.

50-ms depolarizing pulses were used to elicit Na⁺ current from channel isoforms expressed in HEK cells before and after the application of 1 µM CvIV4. Cells were held at −100 mV. Depolarizing potentials ranged from −100 to +120 mV in 5-mV increments. A. Currents not inactivated at 5 ms in the presence of 1 µM toxin were plotted as the percentage increase in the fraction of current at 5 ms (I_{5 ms}). B. Effects of CvIV4 on steady-state activation and inactivation of Na⁺ channel isoforms.