Figure 3. Effect of subcutaneous morphine on cumulative pain scores caused by an incision. In saline-treated rats (A) and in morphine-treated rats (B) on the day of surgery. C and D are of 1 day after surgery. *P < 0.05 vs. 0 min by Friedman and Dunnett's test. (dagger)P < 0.05 vs. saline by Mann-Whitney rank sum test. Each dot is one score; the horizontal line represents the median.