Figure 3.

Use-dependent HERG channel blockade by 3 μM amitriptyline. (A) Tail currents were recorded at −60 mV after a 0.5 s depolarizing pre-pulse to +30 mV from a holding potential −60 mV every 3 s, 12 s, and 36 s, respectively. (B) The HERG channel blockade data from A were plotted against the number of test pulses. (C) Steady-state blockade by 3 μM amitriptyline after 16 pulses at 3 s intervals. Increasing the depolarization intervals to 36 s in the presence of amitriptyline resulted in a partial relief, and changing back to 3 s intervals increased HERG channel blockade again. Symbols with error bars in A and B represent mean±s.e.mean: each data obtained from six cells. Symbols in C is representative of six experiments.