Exercise Reduces Morphine-Induced Hyperalgesia and Antinociceptive Tolerance

Figure 4

Exercise training prevented the development of morphine antinociceptive tolerance in the (a) hot-plate test and (b) tail-flick test. Rats received exercise training for 30 minutes every afternoon. Morphine 30 mg/kg was injected daily, and behavior tests were performed 30 minutes after morphine subcutaneous injection. “a” denotes the statistically significant difference compared to the sedentary+saline group, and “b” denotes the statistically significant difference compared to the sedentary+morphine group.

(a)

(b)