title: Estrogen-induced memory enhancements are blocked by acute bisphenol A in adult female rats: role of dendritic spines.
abstract: Acute effects of bisphenol (BPA), an environmental chemical, on estradiol (17α or β-E2)-dependent recognition memory and dendritic spines in the medial prefrontal cortex and hippocampus were investigated in adult female rats. Ovariectomized rats received BPA 30 min before or immediately after a sample trial (viewing objects), and retention trials were performed 4 h later. Retention trials tested discrimination between old and new objects (visual memory) or locations (place memory). When given immediately after the sample trial, BPA, 1-400 μg/kg, did not alter recognition memory, but 1 and 40 μg/kg BPA, respectively, blocked 17β-E2-dependent increases in place and visual memory. When ovariectomized rats were tested with 17α-E2, 1 μg/kg BPA blocked place memory, but up to 40 μg did not block visual memory. BPA, given to cycling rats at 40 μg/kg, blocked visual, but not place, memory during proestrus when 2 h intertrial delays were given. Spine density was assessed at times of memory consolidation (30 min) and retention (4 h) after 17β-E2 or BPA + 17β-E2. In prefrontal cortex, BPA did not alter E2-dependent increases. In the hippocampus, BPA blocked E2 increases in basal spines at 4 h and was additive with E2 at 30 min. Thus, these novel data show that doses of BPA, below the current Environmental Protection Agency safe limit of 50 μg/kg, rapidly alter neural functions dependent on E2 in adult female rats.
authors.affiliation: Department of Psychology, Hunter College of City University of New York, 695 Park Avenue, New York, New York 10065, USA.
authors.forename: T
authors.initials: T
authors.lastname: Inagaki
authors.forename: M
authors.initials: M
authors.lastname: Frankfurt
authors.forename: V
authors.initials: V
authors.lastname: Luine
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds; D049229:Dendritic Spines / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D006056:Golgi Apparatus / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D008568:Memory / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology*; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D004958:Estradiol; D004967:Estrogens; D010636:Phenols; C006780:bisphenol A; D000098826:Bisphenol A Compounds