Figure 3.

Representative current traces (in control conditions and in one representative concentration for each compound) evoked by 40 ms test pulses from −100 mV to 0 mV in the absence (traces 1 and 3) and presence (traces 2 and 4) of a 2.5 s inactivating prepulse introduced before the test pulse. All currents were normalized to the peak current in control conditions without an inactivating prepulse (trace 1). In control conditions, the inactivating prepulse caused a reduction in the current elicited by the test pulse, owing to slow inactivation, from which channels did not recover during the 10 ms repolarization (compare traces 1 and 2). Note that the channel blockade achieved by drug concentrations in the range of the IC₅₀ for rest block was more than 90% with slow inactivation.