ABSTRACT
Long-term exposure to opiates induces physical and psychological dependency. Despite a large number of studies on this subject, cellular mechanism involved in this phenomenon is not yet exactly clear. In this study, we investigated the effects of donepezil, an acetylcholine esterase inhibitor, on morphin-induced withdrawal symptoms in rats. In this experimental study,6 groups of male Sprague Dawly rats weighting between 225 and 300 g, received 10 mg/kg, ip morphine/ day in addition to 1 ml/kg,ip saline or 0.5, 1 and 1.5 mg/kg, ip donepezil. In order to induce dependency, morphine was administered subcutaneously every 12 hours for nine days. On the ninth day, 30 minutes after the last dose of morphine, control groups received 1 ml/kg, ip saline and experimental groups received ip donepezil. After 30 min, naloxone [4 mg/kg, ip] were administered for all groups and the withdrawal symptoms including: jumping, rearing, genital grooming, abdomen writhing, body grooming and wet dog shake, were recorded for 60 minutes. Our results showed that donepezil decreased withdrawal symptoms, also it could attenuate the total withdrawal score, significantly. The results of this study showed that donepezil as an acetylcholine esterase inhibitor, could decrease withdrawal symptoms in rats