Figure 2. (A) Effect of intrathecal morphine administered before or after incision on nonpunctate mechanical hyperalgesia from 1 h to 6 days later. (B) Withdrawal frequency to pinprick. The results are expressed as the mean +/- SD. Pre = time before foot incision. MS = morphine sulfate. *P < 0.05 versus pre by Friedman and Dunnett's test. (dagger)P < 0.05 versus saline by Kruskal-Wallis and Dunn's test.