Figure 5. β-catΔE3 shifts steady-state activation of the Na⁺ channel to the right side and accelerates Na⁺ channel recovery from inactivation, but does not affect other kinetics.

(A) Traces representative of normalized Na⁺ currents recorded at voltage of −35 mV from CTNNB1 E3^+/+, CTNNB1 E3^+/− and CTNNB1 E3^−/− VMs. (B, C) Time constants of activation and inactivation obtained from single exponential fit. One-way ANOVA analysis showing that there is no significant difference in tau activation and inactivation of I_Na among CTNNB1 E3^+/+ (n=14), CTNNB1 E3^+/− (n=11 from 5 mice) and CTNNB1 E3^−/− (n=13 from 6 mice) VMs. (D) Voltage-dependent steady-state activation of Na⁺ channel shifted to the right side by 8 mV in CTNNB1 E3^−/− (n=9 from 3 mice) and CTNNB1E3^+/− (n=8 from 4 mice) VMs compared to that in CTNNB1 E3^+/+ VMs (n=12 from 8 mice). Statistical analyses using one-way ANOVA with Bonferroni post-hoc test on V_1/2 and K slope factor. (E) One-way ANOVA analysis showing that voltage-dependent steady-state inactivation of Na⁺ channel is not significantly different among CTNNB1 E3^+/+ (n=12 from 5 mice), CTNNB1 E3^+/− (n=8 from 4 mice) and CTNNB1 E3^−/− (n=9 from 4 mice) VMs. (F) I_Na recovery traces recorded from CTNNB1 E3^+/+ (n=13 from 5 mice), CTNNB1E3^+/− (n=10 from 4 mice) and CTNNB1 E3^−/− (n=9 from 7 mice) VMs, respectively. (G) Mean ± SEM normalized recovery data for peak I_Na plotted and well described by single exponential. CTNNB1 E3^+/− and CTNNB1 E3^−/− accelerate the Na⁺ channel recovery from inactivation compared to CTNNB1 E3^+/+ in VMs. Statistical analyses using one-way ANOVA with Bonferroni post-hoc test on Tau and K slope factor.