Fig. 1. Mechanical withdrawal threshold in grams  versus time for the cyclooxygenase-1 selective inhibitor SC560 (  open circles , 1 mg/kg [n = 8];  closed triangles , 0.3 mg/kg [n = 8];  open triangles , 0.1 mg/kg [n = 8]) or vehicle control (  open circles [n = 8]) in 4-week-old animals. Baseline is withdrawal threshold before surgery. Time 0 is 2 h after recovery from surgery and just before administration of study drug or vehicle. A dose-dependent increase drug effect was seen. Actual thresholds were only significantly different from baseline for the 1-mg/kg dose at 2 and 4 h as indicated by the  asterisk , which is  P < 0.05 compared with vehicle control.