title: Role of hippocampal M1 and M4 muscarinic receptor subtypes in memory consolidation in the rat.
abstract: Muscarinic receptors in the hippocampus are relevant to learning and memory, but the role of each subtype is poorly understood. Muscarinic toxins (MTs) from Dendroaspis snakes venom are selective for muscarinic receptor subtypes. MT2, a selective agonist for M(1) receptors, given into the hippocampus immediately after training, improved memory consolidation of an inhibitory avoidance task in rats, whereas the antagonist pirenzepine was amnestic, supporting a facilitatory role of M(1) receptors. Instead, MT3, a selective antagonist at M(4) receptors, caused amnesia. Neither M(1) nor M(4) receptor appeared involved in habituation to a new environment. Thus, our results suggest that memory consolidation of an inhibitory avoidance task in the rat involves the participation of both M(1) and M(4) hippocampal receptors, with a positive modulatory role.
authors.affiliation: Laboratório de Psicobiologia e Neurocomputação, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Posto Alegre, Brazil.
authors.forename: Amâncio Romanelli
authors.initials: AR
authors.lastname: Ferreira
authors.forename: Lucas
authors.initials: L
authors.lastname: Fürstenau
authors.forename: Carlos
authors.initials: C
authors.lastname: Blanco
authors.forename: Edgar
authors.initials: E
authors.lastname: Kornisiuk
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Sánchez
authors.forename: Doriana
authors.initials: D
authors.lastname: Daroit
authors.forename: Mariane
authors.initials: M
authors.lastname: Castro e Silva
authors.forename: Carlos
authors.initials: C
authors.lastname: Cerveñansky
authors.forename: Diana
authors.initials: D
authors.lastname: Jerusalinsky
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Quillfeldt
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004546:Elapid Venoms / Q000633:toxicity; D017815:Elapidae; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D009043:Motor Activity / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009498:Neurotoxins / Q000633:toxicity; D010890:Pirenzepine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D043643:Receptor, Muscarinic M1; D043588:Receptor, Muscarinic M4; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*
chemical_list: D004546:Elapid Venoms; D018727:Muscarinic Antagonists; D009498:Neurotoxins; D043643:Receptor, Muscarinic M1; D043588:Receptor, Muscarinic M4; D011976:Receptors, Muscarinic; D010890:Pirenzepine