BPA and BPS Do Not Affect Tyrosine Hydroxylase
or Swimming Activity in Xenopus laevis Tadpoles
Bisphenol-A (BPA) is a synthetic compound commonly used to make plastics. As an endocrine disruptor (specifically an estrogen antagonist), BPA has been linked to health problems including obesity, diabetes, schizophrenia, hyperactivity, and cancer. As a result, some manufacturers produce “BPA free” products, which frequently contain the BPA analog bisphenol-S (BPS). BPS’s strong structural similarities to BPA allow it to be an effective plasticizer though not necessarily a healthier alternative. Previous experiments in our lab and others have revealed that developing dopaminergic neurons can be compromised by BPA exposure. This experiment compared the influence of BPA and BPS on dopaminergic neurons of Xenopus laevis tadpoles. Embryos were exposed to 0-300 nM BPA or BPS for 96 hours. Immunostaining for tyrosine hydroxylase (TH), an enzyme critical for dopamine production, allowed two-dimensional visualization of midbrain dopaminergic neuronal clusters in the posterior tuberculum via confocal microscopy. Areas of these TH+ neurons were then analyzed using quantitative morphology. Statistical comparisons showed that neither BPA nor BPS altered the 2D area of TH+ neuronal clusters. These null results may be due to an inability to quantify 3D clusters appropriately. We also studied the effects of BPA and BPS on the developing tadpole nervous system by examining swimming behaviors and hyperactivity. BPA has been linked to hyperactivity in both children and zebrafish. We hypothesized that BPA and BPS would cause hyperactivity in tadpoles swimming behavior, but the results showed no influence of BPA or BPS on the swimming behaviors observed. Further measurements of tadpole swimming behavior should be assessed to explore the link between BPA and BPS on hyperactivity.