FIGURE 3.
Activation properties for S4S5 mutants. A, 3-s isochronal activation protocol and example traces of WT. x and y axes are 1 s and 0.25 μA, respectively (panel i). The peak tail currents (*) derived from 3-s isochronal activation were fitted with a Boltzmann equation to derive V0.5 of activation (panel ii). The values for all mutants are summarized in Table 1. B, envelope of tail protocol to elicit the tail current at −70 mV after activation at 20 mV. One of the traces and its respective protocol are highlighted (panel i). The time constants of activation at 20 mV for WT and S4S5 mutants are summarized in panel ii. All summary data are presented as mean ± S.E. and statistical comparisons made using one-way ANOVA with Bonferroni post-test. Significant differences (p < 0.05) are highlighted with asterisks. The values for all mutants are summarized in Table 1.