Fig. 1. Dexmedetomidine (DEX) added to ropivacaine enhanced the duration of dense sensory blockade ( P < 0.005) and time to return to normal sensory function ( P < 0.005) in response to a thermal stimulus in a dose-dependent fashion when compared with the control group, ropivacaine alone. The graph shows the time course of paw withdrawal latency (PWL) values of the baseline taken 24 h before surgery (Baseline; mean value of all rats = 5.46 ± 1.13 s) and at 30-min time points after the sciatic nerve block. Dashed lines represent the time of a dense sensory block (PWL > 14 s) and time to the return of normal sensory function (PWL < 6.59 s).