Effects of Quercetin and ACTH on Morphine-Induced Tolerance and Dependence in Mice

The goal of this study was to evaluate the effects of quercetin and acthinjection on prevention of development of morphine tolerance and dependence inmice. in this study different groups of mice received morphine (40 mg/kg, i.p.) plusquercetin (5, 10, 25 mg/kg, ip), acth (1, 2.5, 5 iu/mice, i.p.), or combination ofquercetin (5 mg/kg) and acth (1 iu/mice) once a day for four days. tolerance wasassessed by administration of morphine (9 mg/kg) and using hot plate test on thefifth day. it was found that pretreatment with quercetin or acth decreased the degreeof tolerance. co-administration of quercetin and acth before morphine did notdecrease the tolerance, significantly. from these results it may be concluded thatadministration of quercetin or acth alone could prevent the development oftolerance to the analgesic effects of morphine. these effects may be related to asnitric oxide inhibitor (enoi) behavior of quercetin and the ability of morphine andtheir receptors in the control of the secretion of crh.