Bisphenol-A antagonizes the rapidly modulating effect of DHT on spinogenesis and long-term potentiation of hippocampal neurons.

Bisphenol A (BPA), a common environmental endocrine disruptor, modulates estrogenic, antiestrogenic, and antiandrogenic effects throughout the lifespan. Recent studies found more obvious adverse effect of BPA on some neurobehavior in males than that in females. In this study, BPA at 10-100 nM rapidly increased the densities of the dendrite spine and synapse in cultured hippocampal neurons of rats in vitro within 1 h. Co-treatment of BPA (100 nM) with dihydrotestosterone (DHT, 10 nM) or with 17β-E (10 nM) completely eliminated the promotion of DHT or 17β-E in the densities of the dendritic spine and synapse. Pretreatment of estrogen receptors (ERs) antagonist ICI182,780 but not of androgen receptors (ARs) antagonist flutamide (Flu) for 30min completely blocked BPA-enhanced densities of the dendritic spine and synapse. Pretreatment of flutamide for 30min before BPA and DHT completely rescued BPA-enhanced densities of the dendritic spine and synapse. Furthermore, pretreatment of ERK1/2 inhibitor U0126 or p38 inhibitor SB203580 entirely eliminated BPA-induced increases in the densities of the dendritic spine and synapse. Meanwhile, BPA (100 nM) enhanced long-term potentiation (LTP) induction of dentate gyrus in hippocampal slices of younger male rats, which was not blocked by co-incubation of flutamide but was inhibited by pretreatment of an P38 inhibitor SB203580. Co-application of BPA with DHT inhibited DHT-suppressed LTP. These results are the first demonstrating the antagonism of BPA to the rapid modification of DHT in synaptic plasticity. However, BPA alone rapidly promotes spinogenesis and synaptic activity through ER instead of AR, and both ERKs and p38 signaling pathways are involved in these processes.