Abstract
We have investigated the low dose effects of bisphenol A (BPA) on the central nervous systems such as the sexually dimorphic brain and behaviors, emotion and neuronal activity. Perinatal exposure to BPA disrupted the sexual dimorphism of the size of locus coeruleus (LC) (Kubo et al. 2003). Pre- and postnatal exposure to BPA both impaired the sexual differentiation of exploratory behavior and enhanced depressive behavior (Fujimoto et al. 2006). In addition, the effects of BPA on general motor activity and avoidance response to predator odor and olfactory responses in medial amygdale (MeA) neurons were examined. The smell of fox predominantly suppressed locomotor activity and enhanced avoidance response in the BPA-treated rats. Male MeA neurons showed selective excitatory responses to predator odors. This type of neurons did not respond to plant odors. In contrast, female neurons did not show such selectivity. The sex difference in this neuronal response pattern was attenuated by prenatal exposure to BPA.We hypothesize that anti-androgenic BPA actions are mainly affected on the sexually dimorphic open-field behaviors. In addition, the results suggested that BPA impaired the formations of olfactory neuronal network system which may be due to perinatal gonadal hormone actions. [J Physiol Sci. 2008;58 Suppl:S148]
