Background and Aim: Opioid dependence and its resultant consequences is a major health problem. Nowadays, many medicinal plants have been used for the treatment of different aspects of opioid addiction. The purpose of the present study was to evaluate the effects of hydroalcoholic extract of E. platyloba on the acquisition of morphine rewarding effects in mice using a conditioned place preference (CPP) paradigm. Methods: Female mice were assigned to 16 groups (n=8). Different doses of morphine (2.5, 5, 10, 15, and 20 mg/kg, s.c.) and E. platyloba extract (25, 50, 100, and 200 mg/kg, i.p.) were injected to evaluate their ability to induce CPP. Two groups, as vehicle control, received saline. For the acquisition experiment, five groups of mice were used. During the conditioning days, one h. before administrating the effective dose of morphine (15mg/kg), the mice received the plant extract (0, 25, 50, 100, and 200 mg/kg, i.p.). Results: Morphine as well as the E. platyloba extract could induce a significant CPP. Moreover, injection of the plant extract before morphine, on the conditioning days, could inhibit the acquisition of morphine-induced CPP in mice. Conclusion: E. platyloba may have therapeutic application in morphine addiction.
