title: Contribution of the basolateral amygdala NMDA and muscarinic receptors in rat's memory retrieval.
abstract: The present study was designed to investigate the involvement of the muscarinic cholinergic receptors in the basolateral amygdala (BLA) in memory retrieval. Also, the possible relationship between the BLA muscarinic cholinergic and the NMDA receptor systems was evaluated in the inhibitory avoidance learning. Male Wistar rats were bilaterally cannulated into the BLAs and memory retrieval was measured in a step-through type inhibitory avoidance apparatus. Intra-BLA microinjection of different doses of a non-selective muscarinic receptor antagonist, scopolamine (0.5-1μg/rat, intra-BLA), 5min before the testing phase dose-dependently induced amnesia. Pre-test intra-BLA microinjection of different doses of NMDA (0.005-0.05μg/rat) reversed scopolamine-induced amnesia and improved memory retrieval. In addition, different doses of a selective NMDA receptor antagonist, D-AP5 (0.001-0.005μg/rat, intra-BLA) potentiated the response of an ineffective dose of scopolamine (0.5μg/rat) to inhibit memory retrieval. It should be considered that pre-test intra-BLA microinjection of the same doses of NMDA or D-AP5 by themselves had no effect on memory retrieval. Similar to ANOVA analysis, our cubic interpolation analysis also predicted that the activation or inactivation of the NMDA receptors by different doses of drugs can affect the scopolamine response. On the other hand, pre-test intra-BLA microinjection of D-AP5 inhibited the reversal effect of NMDA on scopolamine-induced amnesia. It can be concluded that the BLA cholinergic system, via muscarinic receptors, has a critical role in memory retrieval. Our results also suggest that a cooperative interaction between the BLA NMDA and muscarinic acetylcholine receptors modulates memory formation of inhibitory avoidance task in rats.
authors.affiliation: Department of Animal Biology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Efat
authors.initials: E
authors.lastname: Nazarinia
authors.affiliation: Department of Animal Biology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran; School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran. Electronic address: rezayof@khayam.ut.ac.ir.
authors.forename: Ameneh
authors.initials: A
authors.lastname: Rezayof
authors.affiliation: Department of Animal Biology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Sardari
authors.affiliation: School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Nima
authors.initials: N
authors.lastname: Yazdanbakhsh
mesh_terms: D000818:Animals; D066272:Basolateral Nuclear Complex / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D008297:Male; D011939:Mental Recall / Q000187:drug effects*; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012601:Scopolamine / Q000494:pharmacology*; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018727:Muscarinic Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; C056639:2-amino-5-phosphopentanoic acid; D012601:Scopolamine; D014633:Valine
keywords: Basolateral amygdala; Muscarinic receptors; NMDA receptors; Passive avoidance learning; Rat(s)