Figure 6.

A. Effect of SCBIs on the recovery of BgNa_v1-1a sodium channels from prolonged depolarization. The first test pulse (20 ms) was elicited to -10 mV from a holding potential of -30 mV. Thereafter, test pulses (20 ms) to -10 mV were applied from a holding potential of -120 mV at 1 Hz for the first 5 min, then at 0.1 Hz for up to 90 min. Currents were normalized to the largest current recorded during recovery. Averaged data for various concentrations are shown with different symbols, with the number of replicates shown in parentheses. Solid lines superimposed on the graph are calculated from equation 1, with a K_d for DCJW of 25 nM and a Hill coefficient, p, of 0.96. Data at 0 and 1000 nM were taken to represent the time courses of recovery of unblocked (U) and blocked (B) channels, respectively, and values of K_d and p were found by global minimization of the sum of the squares of the point-by-point differences between data at the three lower DCJW concentrations and the time course calculated from Equation 1, as shown by the solid lines superimposed upon the data. B. Similar data and analysis for metaflumizone, except that the time course of B was not directly measurable but was calculated as described in the text and shown by the dashed curve (B_avg).