Scopolamine induced memory impairment; possible involvement of NMDA receptor mechanisms of dorsal hippocampus and/or septum

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• 作者：Fatemeh Khakpai^a ; Mohammad Nasehi^b ; Ali Haeri-Rohani^a ; Akram Eidi^a ; Mohammad Reza Zarrindast^a ; ^c ; ^d ; ^e ; ^f ; ^g ; ^{zarinmr@ams.ac.ir}
• 关键词：NMDA ; D-AP7 ; Scopolamine ; Septo-hippocampal ; Step-through inhibitory avoidance ; Rat
• 刊名：Behavioural Brain Research
• 出版年：2012
• 期刊代码：3_01664328
• 类别：neu
• 出版时间：16 May, 2012
• 卷：231
• 期：1
• 页码：1-10
• 文件大小：1933 K

摘要

Background and aim

The anatomical connections of septum and hippocampus and the influence of cholinergic and glutamatergic projections in these sites have been reported. In the present study, the effect of pre-training intra-dorsal hippocampal (CA1) and intra-medial septal (MS) administration of scopolamine, a nonselective muscarinic acetylcholine antagonist, and NMDA receptor agents and their interactions, on acquisition of memory have been investigated.

Methods

The animals were bilaterally implanted with chronic cannulae in the CA1 regions and in the medial septum. Animals were trained in a step-through type inhibitory avoidance task, and tested 24 h after training to measure step-through latency as memory retrieval.

Results

Intra-CA1 or intra-MS injections of scopolamine (0.5, 1 and 2 渭g/rat) and D-AP7 (a competitive NMDA receptor antagonist; 0.025, 0.05 and 0.1 渭g/rat) reduced, while NMDA (0.125 and 0.25 渭g/rat) increased memory. Intra-MS injection of a subthreshold dose of NMDA reduced scopolamine induced amnesia in the MS. However, similar injection of NMDA into CA1 did not alter scopolamine response when injected into CA1. Moreover, intra-MS or -CA1 injection of a subthreshold dose of NMDA did not alter scopolamine response in the CA1 or MS respectively. On the other hand, co-administration subthreshold doses of D-AP7 and scopolamine into CA1 and/or MS induced amnesia.

Conclusions

The cholinergic system between septum and CA1 are modulating memory acquisition processes induced by glutamatergic system in the CA1 or septum and co-activation of these systems in these sites can influence learning and memory.