Fig. 1. Potent stabilization of Nav1.7 inactivation by CBD.
a Currents before and after application of 300 nM CBD for two minutes at 37 °C. b Time-course of inhibition of hNav1.7 channels by 300 nM CBD at 37 °C. Mean ± SEM, n = 7 cells. c Shift in the voltage-dependence of steady-state channel availability (determined by 5-s prepulses followed by a test pulse to +10 mV) by 300 nM CBD. Closed circles: Peak test pulse current versus prepulse voltage in a representative cell before and after 300 nm CBD. Solid lines: fits to Boltzmann function (control: midpoint −75.2 mV, slope factor 7.9 mV; 300 nM CBD: midpoint −82.6 mV, slope factor 8.4 mV). The dashed line shows the Boltzmann function fitted to CBD data normalized to the control Boltzmann fit to show the shift in voltage dependence. Inset: calculated values for dissociation constants of CBD binding to resting and inactivated states21, using average data from 6 cells. d Slowed recovery from inactivation with CBD, assayed at −100 mV following a 300-ms step to −40 mV to promote binding of CBD to fast inactivated channels (mean ± SEM, n = 6 cells for recovery times ≥ 10 ms, 5–6 cells for times <10 ms). e Time-course of entry into slowly-recovering states during steps to −40 mV in the absence and presence of CBD (mean ± SEM, n = 6 cells). A dashed line is drawn at 20 ms, showing rapid entry of channels into slowly-recovering states consistent with binding to fast inactivated states.