38 巻 (2013) 4 号 p. 539-546
Bisphenol A (BPA) is one of the ‘environmental endocrine disrupters’ (EEDs) released by plastics and resin known to interfere with hormonal responses. In this study, female Wistar rats were exposed to low-dose BPA (24 μg/kg/day) during 7 days after giving birth. The male and female offspring, exposed to the BPA through lactation, were evaluated using an open field test (OFT) at the age of six weeks, an elevated plus maze test (EPM) at seven weeks, and a forced swimming test (FST) at nine weeks. The OFT indicated that females were more active than males, and that BPA selectively increased rearing duration in males, thereby eliminating the gender effect. The results of EPM showed that BPA did not enhance the anxiety-like action; rather, it was associated with an anxiolytic-like action in females. In the FST, not only there was an increase in the immobility time, but also there was reduction of latency observed in BPA rats. It indicated that the depression-like responses were clearly enhanced by the postnatal exposure. Altogether, these data suggest that low-dose BPA ingested by neonates through breastfeeding may cause persistent aberrant behaviors that are relevant to emotions.