Figure 5.
Effects of amitriptyline on rapidly activating delayed rectifier K+ current (IKr) and transient outward K+ current (Ito) in rat atrial myocytes. (A) Voltage clamp pulse protocol was shown in the upper panel. The middle panel was superimposed current traces recorded in high K+ solution (140 mM) before, in the presence, and after wash out of 5 μM E-4031. Disappearance of the time-dependent component of inward currents by E-4031 indicates that this component is IKr. In the lower panel, superimposed current traces before, in the presence, and after wash out of 5 μM amitriptyline were shown. (B) Superimposed current traces recorded in response to depolarizing pulses to +40 mV in normal Tyrode solution, before and after applying 5 μM amitriptyline. Similar observations in two more cells.