اثر تزريق درون هيپوكامپي سيستم كانابينوئيدي بر حافظه موش هاي صحرايي پيش تيمار شده با مورفين

Effect of cannabinoidergic drugs in the dorsal hippocampus of morphine sensitized rats in the memory formation

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 intra-CA1 administration of cannabinoid receptor agonist, WIN55, 212-2 (0.25 and 0.5 jug/rat) and CB1 receptor antagonist, AM251 (25 and 50 ng/rat, intra-CA1) decreased memory retrieval. Administration of AM251 (25, 50 and 100 ng/rat, intra - CA1), 2 min before injection of effective dose of WIN55, 212-2 (0.5 Mg/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.