Figure 4. Effects of flecainide on I_Na decay rate of WT and R1448C hNav1.4 channels.

The I_Na was evoked by 25 ms-long test pulses to –30 mV applied at 0.1 Hz from the V_1/2 of –180 mV before (CTRL) and after application of 100 μm flecainide. To allow direct inspection of drug effect on current decay, I_Na measured during drug exposure was scaled with respect to peak amplitude of control I_Na (dashed line). The parameters τd₁, τd₂ and Q were calculated form the fit of current decay with eqn (5). Each bar represents the mean ± s.e.m. from 8 (WT) and 11 cells (R1448C). Statistical analysis was performed using Student's paired t test, * indicating at least P < 0.01 versus CTRL wild-type and # indicating at least P < 0.02versus relative control.