عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In present study, the effects of intra-dorsal hippocampal (intra-CA1) injection of cannabinoid receptor agents on memory formation have been investigated in 3-days morphine-treated rats. Method: Passive avoidance task of memory has been used to examine for retrieval of memory formation, 24 h after training. morphine was injected subcutaneously (S.C.), once daily for 3-days followed by 5 days free of the morphine before training. Results: Post-training intraandndash;CA1 administration of cannabinoid receptor agonist, WIN55, 212-2 (0.25 and 0.5 andmicro;g/rat) and CB1 receptor antagonist, AM251 (25 and 50 ng/rat, intraandndash;CA1) decreased memory retrieval. Administration of AM251 (25, 50 and 100 ng/rat, intra andndash; CA1), 2 min before injection of effective dose of WIN55, 212-2 (0.5 andmicro;g/rat) decreased the response induced by WIN55, 212-2. Repeated administration of different doses of morphine (2.5, 5 and 10 mg /kg) for 3-days incraesed memory retrieval. However, repeated administration of different doses of morphine (2.5, 5 and 10 mg /kg) for 3-days reversed amnesia induced by WIN55, 212-2. Conclusion: The results suggest that cannabinoidergic and opioidegic system have a close interaction on memory retrieval and WIN55,212-2 influence on memory formation and subchronic morphine pre-treatment may restore memory through a possible opioidergic receptor sensitization.