EFFECTS OF POLYCHLORINATED BIPHENYLS GIVEN PRENATALLY ON THE NEURO-BEHAVIORAL DEVELOPMENT OF MICE

When tested at adulthood, albino mice exposed in utero to 3,4,3′,4′-tetrachlorobiphenyl (TCB) demonstrated signs of neurotoxicity. The most severely affected subjects (TCB-spinners) displayed a neurobehavioral syndrome consisting of intermittent stereotypic circling, head bobbing, and hyperactivity. TCB-spinners were found to be markedly hyperactive during the dark phase of the diurnal phase and showed impaired forelimb grip strength, ability to traverse a wire rod, visual placement responding, and acquisition of one-way avoidance. Some mice did not display the spinning syndrome (TCB-nonspinners), but were found to be deficient in traversing a wire rod and avoidance acquisition. None of the TCB-exposed mice were found to have depressed neuromuscular reflexes in response to a variety of stimuli. Tissue distribution studies demonstrated that TCB levels were not detectable in adult mice following prenatal exposures. The results of these experiments demonstrate that prenatal exposure to TCB can influence neurobehavioral functioning of mice during adulthood and, in some cases, such effects can be observed in the absence of clinical signs of toxicity. © 1979.