Fig. 4. Reversibility of the inhibitory effect of ropivacaine on the ion currents shown in  figure 3 . Current amplitudes were normalized to the predrug control and plotted as a function of the washout time. I^Ca= L-type calcium current; I^K1= inward rectifier potassium current; I^Kr= rapid delayed rectifier potassium current; I^Ks= slow delayed rectifier potassium current; I^to= transient outward current.