FIGURE 4.

Functional regulation of Nav1.6-mediated currents by PLEV and EYYV. (A) Conductance-voltage relationships for Nav1.6 cells co-expressing GFP or FGF14-GFP treated with 0.1% DMSO, 50 µM PLEV and 50 µM EYYV. (B) Comparison of V1/2 of activation between the indicated experimental groups. (C) Normalized current as a function of membrane potential to characterize the effects of 0.1% DMSO, 50 µM PLEV, and 50 µM EYYV on steady-state inactivation. (D) Comparison of V1/2 of steady-state inactivation between the indicated experimental groups. (E) Ratio maximal INa plotted as a function of depolarization cycle to characterize the effects of 0.1% DMSO, 50 µM PLEV, or 50 µM EYYV on entry of Nav1.6 channels into long-term inactivation (LTI) in the presence and absence of FGF14. Cells were subjected to four 0 mV 16 ms depolarizations separated by −90 mV 40 ms recovery intervals. (F) Bar graph represented 2nd, 3rd, and 4th pulse of LTI. (G,H) Characterization of cumulative inactivation of Nav1.6 channels in the presence or absence of FGF14 exposed to 0.1% DMSO, 50 µM PLEV, or 50 µM EYYV. It was examined by applying a 2 ms test pulse to −10 mV, 20 times at frequency10 Hz from a holding potential of −80 mV. Data are mean ± SEM. Significance was assessed using a one-way ANOVA Tukey’s multiple comparisons test. NS = non-significant; *, p value at least < 0.05 (detailed p values and summary of results are reported in Tables 1, 3).