Involvement of α-1-adrenergic receptors in central region of amygdala and the effects of cannabinoid agonist on inhibitory avoidance memory in male rats

There are many similarities between memory impairment in patients suffering from Alzheimer and animals treated by Cannabinoids. The agonists of Cannabinoid receptors affect on a variety of memories and leanings. The present study aims to investigate the role of α-1-adrenergic receptors in central region of amygdala in state-dependent learning induced by WIN55,212-2 (cannabinoid agonist) in rats. Cannulae placement was performed bilaterally in the central amygdala region of male rats. The rats were trained in the avoidance learning apparatus (step-down model). 24 hours after training, the memory was tested by measuring the lag time for stepping down the platform. Injection of WIN55, 212-2 intra central amygdala (dose-dependent, 0.25, 0.5 µg/rat) post-training reduced lag time/latency for stepping down. Injection induced amnesia was reversed by pre-test administration of the same dose of WIN55, 212-2. It is called state-dependent learning. Pre-test intra-central injection of α-1-adrenoceptor agonist, Phenylephrine (0.5, 0.25 µg/rat) improved post-training WIN55, 212-2 (0.5 µg/rat) intra central injection induced retrieval impairment. But intra injection of Prazosin (0.5 µg/rat) 2 minutes before injection of WIN55, 212-2 (0.5 µg/rat) on the testing day inhibited WIN55, 212-2 state-dependent learning. The results suggest that α-1-adrenergic receptors in central region of amygdala are involved in learning which dependent on the state induced by WIN55, 212-