Fig. 2. ( A and B ) Steady state frequency-dependent effects of 100 μm ropivacaine on maximum velocity of depolarization (Vmax) and action potential duration (APD) (n = 5). ( C and D ) Restitution kinetics of Vmaxand APD in the absence and presence of 100 μm ropivacaine (n = 6). The solid line in C was obtained by exponential fitting to determine the dissociation time constant of ropivacaine from the sodium channel. * Significant ( P < 0.05) change from control.