اثر گيرنده هاي آلفا-2 آدرنژيك هيپوكامپ پشتي بر يادگيري وابسته به وضعيت القا شده با 2-212 ، WIN55

The Effect of Dorsal Hippocampal a2-Adrenegic Receptors on WIN55,212-2 State- Dependent Memory of Passive Avoidance

Background and Objectives: Cannabinoids are a class of psychoactive compounds that produce a wide array of effects in a large number of species. In the present study, the effects of bilateral intra- CA1 injections of an a2-adrenergic receptor agents, on WIN55,212-2 state-dependent learning were examined in adult male Wistar rats. Methods: The animals were bilaterally implanted with chronic cannulae in the CA1 regions of the dorsal hippocampus, trained in a step-down type inhibitory avoidance task, and tested 24h after training to measure step-down latency. Results: Post-training intra-CAl injection of WIN55,212-2 (0.25 and 0.5jug/rat) induced impairment of memory retention. Amnesia produced by post-training WIN55,212-2 (0.5jug/rat) was reversed by pre-test administration of the same dose of WIN55,212-2 that is due to a state-dependent effect. Pre­test intra-CAl injection of clonidine (0.5 and 0.75jug/rat, intra-CAl) improved post-training WIN55,212-2 (0.5jug/rat, intra-CAl)-induced retrieval impairment, while pre-test intra-CAl injection of yohimbine (lfig/rat, intra-CAl) 2min before the administration of WIN55,212-2 (0.5|ug/rat, intra- CAl) inhibited WIN55,212-2 state-dependent memory. Conclusion: These results suggest that a2-adrenergic receptors of the dorsal hippocampal CA1 regions may play an important role in Win55,212-2-induced amnesia and WIN55,212-2 state- dependent memory.