Modulationof Neuro-Dopamine Homeostasis in JuvenileFemale Atlantic Cod (Gadus morhua)Exposed to Polycyclic Aromatic Hydrocarbons and Perfluoroalkyl Substances

The dopaminergic effect of PAH and PFAS mixtures, prepared according to environmentally-relevant concentrations, has been studied in juvenile female Atlantic cod (Gadus morhua). Benzo[a]pyrene, dibenzothiophene, fluorene, naphthalene, phenanthrene and pyrene were used to prepare a PAH mixture, while PFNA, PFOA, PFOS, and PFTrA were used to prepare a PFAS mixture. Cod were injected intraperitoneally twice, with either a low (1x) or high (20x) dose of each compound mixture or their combinations. After two weeks of exposure, levels of plasma 17β-estradiol (E2) were significantly high in high PAH/high PFAS treated groups. Brain dopamine:metabolite ratios (DOPAC/dopamine and HVA+DOPAC/dopamine) changed with E2 plasma levels, except for high PAH/low PFAS and low PAH/high PFAS treated groups. On the transcript levels, th mRNA inversely correlated with dopamine: metabolite ratios and gnrh2 mRNA levels. Respective decreases and increases of drd1 and drd2a after exposure to the high PAH dose were observed. Specific...