title: Administration of an inhibitor of estrogen biosynthesis facilitates working memory acquisition in male rats.
abstract: Estradiol is known to improve performance of some working memory tasks in female animals and post-menopausal women. In females the main source of estradiol is the ovary. In addition, in both males and females estradiol is synthesized in extragonadal tissues. The role of non-ovarian estradiol synthesis on cognitive abilities has not been adequately explored. In the sent study we have assessed the effect of an inhibitor of aromatase, the enzyme that produces estradiol from testosterone, on egocentric working memory in male rats. Sprague-Dawley adult male rats received the intra-esophageal administration of the aromatase inhibitor letrozole (2.5 mg/kg), or vehicle. Rats treated with the aromatase inhibitor committed less errors than untreated animals or animals treated with vehicle, when tested in a cross-arms maze. Retention and retrieval stages were unaffected by aromatase inhibition. This finding indicates that aromatase activity is involved in egocentric working memory performance. The effect of the aromatase inhibitor on working memory may be due to the increase in testosterone levels resulting from aromatase inhibition or to modifications in the availability of estradiol in the brain.
authors.affiliation: Laboratorio de Psicobiologia, Centro de Investigacion Biomedica de Michoacan, Instituto Mexicano del Seguro Social, A.P. 7-70 C.P. 58261, Morelia, Mich., Mexico.
authors.forename: Misael
authors.initials: M
authors.lastname: Alejandre-Gomez
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Garcia-Segura
authors.forename: Ignacio
authors.initials: I
authors.lastname: Gonzalez-Burgos
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D047072:Aromatase Inhibitors / Q000008:administration & dosage*; D001522:Behavior, Animal / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects; D000077289:Letrozole; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008570:Memory, Short-Term / Q000187:drug effects* / Q000502:physiology; D009570:Nitriles / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014230:Triazoles / Q000008:administration & dosage*
chemical_list: D047072:Aromatase Inhibitors; D009570:Nitriles; D014230:Triazoles; D000077289:Letrozole