Figure 5.

Effect of treatment of mice with pentoxifylline, indomethacin or morphine on the course of the reaction times to a thermal stimulus (hot plate). Mice were treated i.p. with vehicle (5% NaHCO₃ plus HCl; control), morphine (5 mg kg⁻¹), indomethacin (2 mg kg⁻¹) or pentoxifylline (PTF; 1.6 mg kg⁻¹). Reaction times were measured before injection of the above substances (control time) and 30, 60, and 90 min afterwards. Results are expressed as means±s.e.m. for groups of 5–6 mice. Asterisks indicate statistically significant differences between treated groups and control (^*P<0.001).