RESUMO
Opioid dependence has been causing limitation in usage of morphine and other opioid drugs in pain control. The aim of this study was to assess the effect of short-term forced exercise on withdrawal syndrome in morphine addicted male rats. This experimental study was done in the physiology research center of Ahwas Jondishapour University of Medical Sciences. Twenty four young male Wistar rats, weighing 200-300gr, were randomly divided into four groups: no addiction and no exercise, no addiction and exercise, addiction and no exercise and addiction and exercise. The exercise groups underwent treadmill forced exercise for ten days. The first five days morphine was administrated [ip] twice daily with increasing dose [5, 10, 20, 40, 50 mg/kg] to addicted groups. Also single dose [50mg/kg] of morphine was administrated to them on the 10[th] day of exercise. After administration of naloxone hydrochloride the withdrawal symptoms were evaluated for 5 minutes. The findings of this study were analyzed by SPSS software and One- way ANOVA [Tukey] test. The findings of this study showed that the withdrawal symptoms was elevated in exercise and addicted groups in comparison with control group [p<0.05, p<0.01]. However, most of withdrawal symptoms decreased in addicted and exercise group in comparison with addicted and no exercise group [p<0.01, p<0.001]. The exercise could increase endogenous opioid and withdrawal symptoms in animals but reduce withdrawal symptoms in addicted and exercise groups compared to addicted and no exercise group. Its mechanism might be related to down regulation and low sensitivity of opioid receptors