Fig. 4. Blocking effect of verapamil on wild-type and various mutant hKv1.5 channels. (A) Superimposed hKv1.5 current traces recorded from wild-type (WT) and mutant (T479A, T480A, A501V, I502A, V505A, I508A, A509G, L510A, V512A and V516A) channels during depolarizing steps to +30 mV in the absence (open squares) and presence (filled squares) of 10 mM verapamil. (B) Percent inhibition of wild-type (WT) and various mutant hKv1.5 channels by 10 mM verapamil. The number of experiments was indicated in parentheses. *, P<0.05 compared with wild-type channel.