Figure 5.

Voltage dependence of the unblock rate constants of verapamil and D890. (A) and (B) show hooked tail currents (following a depolarization to +80 mV) at voltages ranging between −60 and −160 mV in presence of 100 μM of either verapamil or D890. In (C) the values of the unblock rate constants, calculated from the decay rate of the tails (see Methods) are plotted as function of voltage. Continuous lines represent the best fit obtained with the following equations (see text for details):

A regression fit to the data produced values of 0.06±0.0017 ms⁻¹ and 0.00038±0.00007 ms⁻¹ respectively for A and B and 0.0034±0.0004 ms⁻¹ for the k_{off (0 mV)} in D890. k values were 40 for verapamil and 36 for D890. Dashed line represents best fit of data points for verapamil using a simple exponential function similar to that used for D890.