Figure 4.

Effect of SxIIIC on the electrophysiological parameters of hNa_V1.7. (a) Voltage-current relationship curves before (black squares) and after addition of SxIIIC (blue triangles). SxIIIC (100 nM) inhibited peak current but did not affect the membrane voltage of peak current. (b) Conductance-voltage relationship before (black open squares) and after addition of SxIIIC (blue open triangles) and voltage-dependence of steady-state fast activation curves before (black squares), and after addition of SxIIIC (blue open triangles). SxIIIC (100 nM) did not shift the V_1/2 of voltage-dependence of activation or V_1/2 of steady-state fast inactivation at hNa_V1.7. (c) Wash out after addition of equipotent peptide (IC₉₀), SxIIIC (1 µM; blue circles) and KIIIA (3 µM; yellow squares). Black arrow indicates peptide addition and grey arrows indicate each subsequent wash out step. Current inhibition was irreversible for SxIIIC over 35 min and was almost irreversible for KIIIA. Data presented as mean ± SEM, with n = 4 cells per data point.