Striatal slices from adult male Wistar-derived rats were exposed to a 1:1 mixture of Aroclor 1254:1260 at concentrations in media of 10, 20, 40, 60 or 100 ppm for 6 hr. Following exposure, slices and media were analyzed by high-performance liquid chromatography for dopamine (DA) and its metabolites. PCBs caused a significant dose-dependent decrease in slice DA content at concentrations greater than 20 ppm. Media concentrations of DA and its metabolites were significantly increased by PCB exposure greater than 60 ppm, indicating that, in addition to their suggested role in inhibiting DA synthesis, PCBs may interfere with either vesicular storage or release of DA. These data suggest that in addition to the recognized action of PCBs in inhibiting tyrosine hydroxylase, PCBs may also interfere with the vesicular monoamine transporter, and thereby suggest an additional mechanism by which DA concentrations and metabolism may be altered by PCB exposure.