Sub-chronic exposure of the adult rat to Aroclor 1254 yields regionally-specific changes in central dopaminergic function.

Laboratory rats were exposed to chow adulterated with either 500 or 1000 ppm Aroclor 1254 for 30 days. Analysis of biogenic amines and their metabolites in the dorsal frontal cortex, lateral olfactory tract, striatum, basal hypothalamus, hippocampus and brainstem revealed significant decreases in dopamine concentrations and metabolism in only the striatum and lateral olfactory tract. Concentrations of individual PCB congeners in the striatum, lateral olfactory tract and hippocampus were measured by gas chromatography with electron capture detection. Neither total concentration nor variations in concentrations of individual congeners between regions could explain this regional specificity. The susceptibility of the striatum and lateral olfactory tract to insult by PCBs may be due to their innervation by midbrain dopaminergic neurons which have been shown to be particularly sensitive to insult from environmental, infectious and pharmacologic agents.