PREGNANCY INCREASES ANXIETY AND IMPAIRS SPATIAL MEMORY IN RODENT DAMS AND ALTERS DENDRITIC ARBORIZATION AND SYNAPTOGENESIS IN NEURONS CULTURED FROM BPA-EXPOSED EMBRYOS

Bisphenol-A (BPA) is an endocrine disrupter that alters a variety of neural, physiological, and behavioral measures. At present, the United States Environmental Protection Agency considers 50 µg/kg/day to be safe, (U.S.E.P.A., 1993). Our labs examined the effects of short-term, low-dose BPA exposure (40 µg/kg/bodyweight) during rodent gestation (embryonic days 7-18). Pregnant dams received saline or BPA (0.25 µg/ml in H₂0) during embryonic days 7-18. Aged matched, virgin females severed as a control group. Anxiety was tested using the zero-maze on pregnancy day 11 and 17. Spatial memory was tested using the object placement tasks with varying inter-trial delays across pregnancy days 12-15. Hippocampal neuron development in culture from E18 pups and the dendritic spine density in dams was measured. Anxiety was increased in pregnancy, regardless of BPA exposure, compared to nonpregnant controls on both day 11 and 17 with pregnant females spending more time in the closed vs open arm of the zero-maze. Spatial memory was impaired on day 15 during the 2 hr object placement delay trial of pregnant females compared to the pregnant + BPA and nonpregnant groups. Preliminary data show decreased dendritic arborization and synaptogenesis in neurons cultured from BPA-exposed pups. Analysis of spine density in dams is ongoing. These data indicate that BPA effects may be different in pregnancy than in previous studied time periods and highlight the need to understand the behavioral and neuronal implications of low-dose BPA exposure during times of developmental vulnerability.