Effects of environmental chemicals on emotional behaivor and the brain

Abstract

The effects of environmental chemicals on sexual differentiation of exploratory behavior and emotional behaviors and brain were investigated. We exposed bisphenol A (BPA, 0.05-5 ppm) to mother rats pre-, peri- or postnatal period or 1-bromopropane (1-BP, 700 ppm) for 6 h/day during prenatal period. In the open field test, control females explored more frequently than males. This sex difference was not affected by neonatal BPA treatment but was abolished by pre- and perinatal treatment or 1-BP. The time spent in open arms in the elevated plus maze test decreased by neonatal or prenatal BPA treatment although sex difference was not clearly affected. In the forced swimming test, both prenatal and neonatal BPA exposures increased immobility time, an index of depressive behavior, in male rats and reduced immobility latency in both sexes. The duration of immobility decreased in the forced swimming test and the sex difference were disappeared by 1-BP. These findings suggest that prenatal BPA or 1-BP exposure is more effective to impair sexual differentiation of exploratory behavior than neonatal BPA exposure but neonatal period is also important for development of emotional behavior [J Physiol Sci. 2006;56 Suppl:S22]