Fig. 4.

Effect of veratridine on inactivation of Nav1.7 currents. a Representative steady-state inactivation currents (arrow) and sustained currents (arrowhead) modified by 75 µM veratridine when cells were excited from a holding potential of –100 mV to −40 mV for 500 ms followed by a test pulse of –10 mV for 50 ms. b Steady-state inactivation curve of Nav1.7 currents, excited from a holding potential of −120 mV to −20 mV for 500 ms following a step pulse to −10 mV for 50 ms, in the presence and absence of 75 µM veratridine. Curves were fitted with the Boltzmann equation, where V_1/2 = −59.66 ± 0.18 mV, k = 5.34 ± 0.16 mV for the control; V_1/2 = −69.91 ± 0.32 mV, k = 5.63 ± 0.28 mV after veratridine treatment; and V_1/2 = −63.26 ± 0.18 mV, k = 4.81 ± 0.16 mV for drug washout, n = 5. c Steady-state inactivation curve of Nav1.7 currents in the presence and absence of 500 nM TTX fitted with the Boltzmann equation, where V_1/2 = −62.33 ± 0.17 mV, k = 4.58 ± 0.15 mV for the control; V_1/2 = −70.85 ± 0.59 mV, k = 5.98 ± 0.52 mV after TTX treatment, n = 3