title: Muscarinic receptors activity in the perirhinal cortex and hippocampus has differential involvement in the formation of recognition memory.
abstract: In this work we probed the effects of post-trial infusions of the muscarinic receptor antagonist scopolamine on object recognition memory formation. Scopolamine was infused bilaterally immediately after the sample phase in the perirhinal cortex or dorsal hippocampus and animals were tested for short-term (90 min) or long-term (24 h) memory. Results showed that scopolamine impaired short-term memory when injected in either the perirhinal cortex or hippocampus. Nevertheless, scopolamine disrupted long-term memory when administrated in the perirhinal cortex but not when applied in the hippocampus. Long-term memory was unaffected when scopolamine was infused 160 min after the sample phase or 90 min before test phase. Our data indicate that short-term recognition memory requires muscarinic receptors signaling in both the perirhinal cortex and hippocampus, whereas long-term recognition memory depends on muscarinic receptors in the perirhinal cortex but not hippocampus. These results support a differential involvement of muscarinic activity in these two medial temporal lobe structures in the formation of recognition memory.
authors.affiliation: División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-253, 04510 México D.F., Mexico. balderas@ifc.unam.mx
authors.forename: Israela
authors.initials: I
authors.lastname: Balderas
authors.forename: Jean-Pascal
authors.initials: JP
authors.lastname: Morin
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Rodriguez-Ortiz
authors.forename: Federico
authors.initials: F
authors.lastname: Bermudez-Rattoni
mesh_terms: D000818:Animals; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D057567:Memory, Long-Term / Q000187:drug effects / Q000502:physiology*; D008570:Memory, Short-Term / Q000187:drug effects / Q000502:physiology*; D018727:Muscarinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*; D021641:Recognition, Psychology / Q000187:drug effects / Q000502:physiology*; D012601:Scopolamine / Q000494:pharmacology; D013702:Temporal Lobe / Q000187:drug effects / Q000502:physiology*
chemical_list: D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D012601:Scopolamine