بررسي اثر تجويز داخل هسته آكومبانس عصاره الكلي زعفران (Crocus sativus) بر كسب و بيان ترجيح مكان شرطي شده ناشي از مورفين در موش هاي بزرگ آزمايشگاهي

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

Introduction: Previous studies have shown the effects of water extract of Crocus sativus on the euphoric and behavioral properties of morphine in mice. 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. Methods: This study was conducted on 78 male rats that were divided in 13 groups (n = 6 each 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 drugʹs ability to induce place preference. In the second phase of the experiments, the extract of the C. sativus (1,5 and 10 jag/rat), was administered into the nucleus accumbens shell during or after induction of morphine CPP. Then, CPP was tested in the animals. One-way Analysis of Variance (ANOVA) was preformed for statistical procedure. Results: Administration of morphine (0.5, 1, 5, 7.5 and 10 mg/kg), increased the time spent in the compartment paired with morphine (i.e. conditioned place preference-CPP) (P<0.05). This increase reached significance at the dose of 10 mg/kg. Injection of the same doses of the extract (1,5 and 10 jig/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 jxg/rat of the extract (P < 0.0001). In addition, injection of the plant extract (1, 5 and 10 ng/rat) in to the shell part of nucleus accumbens in the test day to the animals that received morphine (10 mg/kg) in the conditioning days decreased the expression of morphine CPP in the animals. This effect was statistically significant for doses 5 and 10 (xg/rat of the extract (P < 0.0001). Conclusion: It may be concluded that intra-accumbens shell compartment injection of the alcoholic extract of C sativus can inhibit the acquisition and expression of morphine-induced CPP and then shift it to the aversive state in rats.