Use-dependent modulatory effect of veratridine on Nav1.7 peak current and tail current. a Typical traces showing the effect of veratridine (75 µM) on Nav1.7 currents, which were activated from a holding potential of −100 to −10 mV (5 ms duration) at 2 Hz, 10 Hz, and 40 Hz. b Statistics on the amplitude of the tail current induced by veratridine (75 µM), evoked as in a after 10 s of depolarization at different frequencies (n = 4). c, d Statistics on the peak current (c) and tail current (d) for each pulse (both normalized to the value at the first pulse) from pulse 1 to pulse 6 as in a at different frequencies (n = 3). Paired Student’s t test, *P < 0.05, **P < 0.01, ***P < 0.001 vs 2 Hz