Fig. 3. Thermal withdrawal latency versus time for the cyclooxygenase-1 inhibitor (SC560) in 2- and 4-week-old animals. The dose of SC 560 was 1 mg/kg. There was a significant increase in thermal latencies in the 2-week-olds animals (n = 10) over time ( P < 0.05 compared with predrug value). There was no effect in the 4-week-old animals (n = 8). There was a significant difference between age groups ( P < 0.05). * P < 0.05 compared with vehicle control for the 2-week-old animals.