title: Estrogen effects on object memory and cholinergic receptors in young and old female mice.
abstract: We investigated whether object recognition memory is modulated by estrogen in young (5 month) and aged (24 month) female C57Bl/6J mice, and if cholinergic muscarinic receptors might contribute to this response. Mice that were ovariectomized, or ovariectomized plus estradiol-treated three weeks before behavioral testing or quantitative autoradiography were compared to intact mice. Memory for a previously encountered object deteriorated significantly between 3 and 6h after initial exposure, regardless of animal age. In both young and aged mice, estradiol-treated mice showed significantly greater recall than did ovariectomized mice. In both age groups, the apparent number of [(3)H]pirenzepine/M(1)-like and [(3)H]AFDX384/M(2)-like muscarinic receptor binding sites was reduced in the basal forebrain as well as its projection areas following ovariectomy, but this decrease was not alleviated by estrogen. Aging poorly affected object memory, but reduced muscarinic binding in some cortical subregions and in the caudate nucleus. These findings suggest that estrogen effects on memory in C57Bl/6J mice are not due to changes in the number of muscarinic receptors.
authors.affiliation: Douglas Hospital Research Center, H4H 1R3, Verdun, Québec, Canada.
authors.forename: Elvire
authors.initials: E
authors.lastname: Vaucher
authors.forename: Isabelle
authors.initials: I
authors.lastname: Reymond
authors.forename: Robert
authors.initials: R
authors.lastname: Najaffe
authors.forename: Satyabrata
authors.initials: S
authors.lastname: Kar
authors.forename: Rémi
authors.initials: R
authors.lastname: Quirion
authors.forename: Marilyn M
authors.initials: MM
authors.lastname: Miller
authors.forename: Keith B J
authors.initials: KB
authors.lastname: Franklin
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001345:Autoradiography; D002540:Cerebral Cortex / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005556:Form Perception / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D010052:Ovariectomy; D010276:Parasympatholytics / Q000494:pharmacology; D010890:Pirenzepine / Q000031:analogs & derivatives* / Q000494:pharmacology; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D011950:Receptors, Cholinergic / Q000187:drug effects*; D011976:Receptors, Muscarinic / Q000187:drug effects
chemical_list: D010276:Parasympatholytics; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; C065959:AFDX 384; D010890:Pirenzepine; D004958:Estradiol