study of the effects of intra-nucleus accumbens shell injections of alcohlic extract of crocus sativus on the acquisition and expression of morphine-induced conditioned place preference in rats

background: previous studies have confirm the effects of water extract of crocus sativus on the euphoric and behavioral properties of morphine in mice. objective: in the present study, the effects of intra-accumbal administration of alcohol extract of crocus sativus stigma on the acquisition and expression of morphine-induced conditioned place preference (cpp) in male wistar rats (250-300 g) were investigated. material and methods: this experimental study was conducted on the 78 male rats that were divided in 18 groups (n=6/group). in a pilot study, different doses of morphine (0.5, 1, 2.5, 5, 7.5 and 10 mg/kg) were injected to the animals for evaluation of the drug's ability to induction of place preference. in the second phase of the experiments, the extract of the c. sativus (1, 5 and 10 µg/rat), was administered into the nucleus accumbens shell during or after induction of morphine cpp. then, cpp were tested in the animals. one-way analysis of variance (anova) was proformed for statistical procedure. results: administration of morphine (0.5, 1, 5, 7.5 and 10 mg/kg), indcreased the time spend in the compartment paired with morphine (i.e. conditioned place preference-cpp). the increament was significant for the dose 10 mg/kg of morphine. injection of the same doses of the extract (1, 5 and 10 µg/rat) 5 min before morphine (10 mg/kg) administration, caused a decrease in the time spent in drug-paired side in doses 5 and 10 µg/rat of the extract. in addition, injection of the plant extract (1, 5 and 10 µg/rat) in to the shell part of nucleus accumbens in the test day to the animals in which reveived morphine (10 mg/kg) in the conditioning days decreased the expression of morphine cpp in the animals which was statisticaly significant for doses 5 and 10 µg/rat of the extract. conclusion: it could be concluded that intra-accumbens shell compartment njection of the alcoholic extract of c sativus can inhibit the acquisition and expression of morphine-induced cpp and shift it to the aversive state in rats. .