By Allison Fletcher

Faculty Mentor: Dr. Dianne Baker

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a group of environmental contaminants that have been found to cause disruptions to the nervous and endocrine systems. One PFAS, perfluorooctanesulfonate (PFOS) is considered one of the most disruptive PFAS to the nervous system. PFOS has been found to disrupt neurodevelopment of the dopaminergic system, which has been linked to neurodevelopmental disorders like Attention Deficit/Hyperactivity Disorder (ADHD) in humans. I hypothesized that PFOS exposure disrupts the development of the dopaminergic system. To test this hypothesis, I exposed zebrafish to 0.05, 0.5, and 5.0 mg/L PFOS through 5 days of embryonic and larval development. To assess acute effects of PFOS on the dopaminergic system, I measured transcript levels of genes that are crucial to the dopamine transport, synthesis, degradation, and signaling in samples collected at 5 days post-fertilization. To test for long-term effects of PFOS exposure, the fish not collected at 5 days were reared until 60 days post-fertilization, when their brains were dissected and used for gene expression analysis. The enzyme that synthesizes dopamine, tyrosine hydroxylase, was significantly upregulated in samples collected at 5 days post fertilization that were exposed to the highest concentration of PFOS (p < 0.001). This data suggests that PFOS can disrupt the dopaminergic system.