Changes in brain monoamine levels in neonatal rats exposed to bisphenol A at low doses

To examine whether exposure to bisphenol A (BPA) at low levels affect brain function, monoamine concentrations in hippocampus, striatum and brain stem, were investigated in neonatal male rats injected intracranially with BPA at 0-10 mu g kg(-1). Significant increases of serotonin (5-HT) in hippocampus, 5-HIAA and 5-HIAA/5-HT in brain stem, dopamine (DA) and DOPAC in striatum were observed at 28 d after the injection on postnatal day 2. At 7 d after the injection, increases in 5-HT and norepinephrine (NE) and decreases in DOPAC and 5-HIAA were observed in hippocampus. To investigate the degradation of BPA in brain, we also measured BPA concentrations of whole neonatal rat brain. Free BPA disappeared from brain tissues within 5 h, even when the highest dose (1000 mu g kg(-1)) was injected. The present results suggest that BPA exposure at lower doses than environmentally relevant levels may have a great impact on monoamine levels in neonatal brain over 28 d after its disappearance. (C) 2009 Elsevier Ltd. All rights reserved.