Fig. 3.
Biophysical properties of SCN5A coexpressed with PMCA4b and nNOS without SNTA1 (labeled as SCN5A), with WT-SNTA1, or with A390V-SNTA1. (a) Whole-cell current traces from representative cells show increased peak INa associated with A390V-SNTA1. (Inset) INa was elicited by test depolarization to 24 ms from a holding potential of −140 mV. (b) Summary data of peak INa densities from each group (n = 9–16). (c) Representative traces showing increased late INa due to A390V-SNTA1 compared with WT-SNTA1 and A390V-SNTA1 plus l-NMMA. (Inset) Currents were elicited by a test depolarization pulse from −140 mV to −20 mV for 700 ms. (d) Summary data for late INa normalized to peak INa after leak subtraction. Late INa was measured as the mean between 600 and 700 ms after the initiation of the depolarization (n = 4–18). Symbols represent means, and bars represent the SEM. *, P < 0.05 versus WT-SNTA1.