NEUROCHEMICAL EFFECTS OF CONSUMPTION OF GREAT-LAKES SALMON BY RATS

This study, part of a larger project to determine the health consequen ces of both perinatal and adult exposure to contaminated salmon hom th e Great Lakes, determined the neurochemical effects of exposure of rat s to chow adulterated with lyophilized salmon fillets. Concentrations of biogenic amines, their metabolites, and choline acetyltransferase ( ChAT) were determined in the frontal cortex (FC), nucleus accumbens, c audate nucleus (CN), hippocampus (HC), and substantia nigra (SN) of ad ult rats who had been exposed, both perinatally and as adults, to stan dard rat chow adulterated with either 5 or 20% (w/w) lyophilized fille ts from either Lake Huron (LH) or Lake Ontario (LO) salmon. Dopamine ( DA) concentrations in the FC were significantly decreased following ex posure to both 20% fish diets. CN DA concentrations were significantly reduced in rats exposed to all diets, while SN DA was decreased only in the LO20-fed animals. SN norepinephrine concentrations were reduced in all groups except for the LO5-fed rats. 3,4-Dihydroxyphenylacetic acid (DOPAC) concentrations in the FC were significantly increased in the LH20 and LO5 groups, while CN DOPAC concentrations were reduced in LH20, LO5, and LO20 animals. 5-Hydroxyindoleacetic acid concentration s were reduced in the FC and CN of all animals exposed to diets adulte rated with Great Lakes salmon. ChAT concentrations were unaffected in rats exposed to any of the adulterated diets. The significant reductio ns in DA, particularly in the FC and CN, suggest that either fish-born e contaminants or consumption of fish, per se, may affect behaviors th at require inhibition of normal responding. We conclude that consumpti on of contaminated fish from the Great Lakes may result in sufficient reductions in biogenic amine function to result in significant deficit s in important behavioral functions in the rat and, by inference, in t he perinatally exposed human. (C) 1998 Academic Press.