title: Scopolamine induced memory impairment; possible involvement of NMDA receptor mechanisms of dorsal hippocampus and/or septum.
abstract: OBJECTIVE
  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 24h after training to measure step-through latency as memory retrieval.
  
  
  RESULTS
  Intra-CA1 or intra-MS injections of scopolamine (0.5, 1 and 2 μg/rat) and D-AP7 (a competitive NMDA receptor antagonist; 0.025, 0.05 and 0.1 μg/rat) reduced, while NMDA (0.125 and 0.25 μg/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.
authors.affiliation: Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Science and Research Branch, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Khakpai
authors.forename: Mohammad
authors.initials: M
authors.lastname: Nasehi
authors.forename: Ali
authors.initials: A
authors.lastname: Haeri-Rohani
authors.forename: Akram
authors.initials: A
authors.lastname: Eidi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zarrindast
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D018680:Cholinergic Antagonists / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008568:Memory / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced / Q000378:metabolism*; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D012601:Scopolamine / Q000494:pharmacology*; D020665:Septum of Brain / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018680:Cholinergic Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D012601:Scopolamine