تاثيرگيرنده هاي موسكاريني ناحيه هيپوكامپ پشتي بريادگيري وابسته به وضعيت كانابينوييدها در مدل يادگيري اجتنابي مهاري

Influence of intracerebral administration of muscarinic agents in dorsal hippocampus (CA1) on cannabinoid state-dependent memory in the step-down passive avoidance test

In the present study, the effects of muscarinic agents on WIN55, 212-2 induced state- dependent memory of passive avoidance task were examined in mice. One-trial step-down paradigm was used for the assessment of memory retention in adult male NMRI mice. Post- training intra-CAl administration of cannabinoid receptor agonist, WIN55, 212-2 (0.5 and 1 jig/mouse) decreased the memory retrieval. Amnesia induced by post-training WIN55, 212-2 (l^g/mouse) was significantly reversed by pre-test administration of WIN55,212-2 (0.5, l|ng/mouse, intra-CAl), and induced WIN55, 212-2-state-dependent memory. Administration of scopolamine (4 jig/mouse) but not physostigmine (0.25,1 and 4 jig/mouse) intra-CAl, 5 min before test by itself decreased the memory retrieval. On the other hands, the animals in which retrieval was impaired, due to WIN55, 212-2 (l^g/mouse) post-training administration, pre¬test administration of physostigmine (1 and 4 jig/mouse) and scopolamine ( 4 jig/mouse) intra- CAl 24 hr after train in dayʹs test restored, memory retrieval. Furthermore animals under influence of post-training administration of WIN55, 212-2 (1 jig/mouse), pre-test co¬administration of non-effective doses of WIN55, 212-2 (0.25 jig/mouse) and scopolamine (1 jig/mouse), increased the restoration of memory by the WIN55, 212-2. These findings may implicate the involvement of muscarinic receptor in state-dependent memory induced by intra-CAl administration of the WIN55, 212-2.