Figure 7.

Slower time to peak of the resurgent Na⁺ currents in the p.V781I and p.A1737T mutant channels. (A) The time to peak in resurgent Na⁺ current was measured using the same protocol as in Figure 4. The value of time to peak plotted against the repolarization potentials for the WT and the p.V781I and p.A1737T mutant channels. The time to peak for the resurgent Na⁺ current was significantly shorter in the WT channel than in the p.V781I and p.A1737T mutant channels, at variable repolarization membrane potentials between −20 and −70 mV (* p < 0.05). (B) The reciprocal time constants (1/tau) for the decay phase of resurgent Na⁺ currents were plotted against the repolarizing potentials in semilogarithmic scales for the WT and the p.V781I and p.A1737T mutant channels. The lines were linear regression fitted using the formulas 1/tau_(V) = 0.2 × exp(−0.6 V/25) ms⁻¹, 0.1 × exp(−0.9 V/25) ms⁻¹, and 0.1 × exp(−0.8 V/25) ms⁻¹ for the WT and the p.V781I and p.A1737T mutant channels, respectively. “V” is the membrane potential in mV.