Role of hippocampal M1 and M4 muscarinic receptor subtypes in memory consolidation in the rat.
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.
Ferreira
Amâncio Romanelli
AR
Laboratório de Psicobiologia e Neurocomputação, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Posto Alegre, Brazil.
Fürstenau
Lucas
L
Blanco
Carlos
C
Kornisiuk
Edgar
E
Sánchez
Gonzalo
G
Daroit
Doriana
D
Castro e Silva
Mariane
M
Cerveñansky
Carlos
C
Jerusalinsky
Diana
D
Quillfeldt
Jorge A
JA
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*
D004546:Elapid Venoms; D018727:Muscarinic Antagonists; D009498:Neurotoxins; D043643:Receptor, Muscarinic M1; D043588:Receptor, Muscarinic M4; D011976:Receptors, Muscarinic; D010890:Pirenzepine