Figure 1

Effect of epidural ropivacaine treatment on thermal hyperalgesia in CCI rats. (a) The latencies for paw withdrawal on the ipsilateral (left panel) and contralateral (right panel) sides in response to thermal stimuli applied to the corresponding hindpaw pad in rats with CCI were evaluated. Ropivacaine (open circles) or saline (closed circles) was epidurally administered once daily from days 7 to 13, as indicated by the horizontal bars. **p < 0.01 and ***p < 0.001 compared with the values in CCI rats treated with saline on the corresponding days by an unpaired t-test (n = 8-9). ^### p < 0.001 compared with the values on the preoperative day by Dunnett's multiple comparison test (n = 8-9). (b) The dose-dependent effects of epidural ropivacaine on the thermal hyperalgesia were examined at day 10. ^## p < 0.01 and ^### p < 0.001 compared with the values in CCI rats treated with saline by Dunnett's multiple comparison test (n = 4-9). (c) The duration of analgesia induced by ropivacaine was examined. Ropivacaine was epidurally administered once daily from days 7 to 10, as indicated by the horizontal bars. ^# p < 0.05 compared with the values before ropivacaine administration at day 7 by Dunnett's multiple comparison test (n = 4).