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BEHAVIORAL ASSESSMENTS OF ADULTS RATS EXPOSED PERINATALLY TO PCB153.
Citation:
Bushnell, P J., T E. Samsam, M. M. Taylor, AND K M. Crofton. BEHAVIORAL ASSESSMENTS OF ADULTS RATS EXPOSED PERINATALLY TO PCB153. Presented at Society of Toxicology, San Francisco, CA, 3/25-29/2001.
Description:
Ortho-substituted polychlorinated biphenyl (PCB) congeners are more neurotoxic in vitro than are non-ortho-substituted PCB congeners. We selected PCB153, a common ortho-substituted PCB congener, to evaluate the neurobehavioral toxicity of this class of PCBs in vivo. Pregnant female Long-Evans rats were given daily oral doses of PCB153 at 0, 5, or 60 mg/kg from gestation day 6 through postnatal day 21 (weaning). Male and female offspring (n = 6 - 8 /sex /dose) of these dams were trained as adults to perform a visual signal detection task (SDT) designed to assess sustained attention. Acquisition of lever-pressing via auto-shaping was not significantly affected by prior exposure to PCB153. During acquisition of the visual discrimination necessary for the SDT, the location of the signal light was moved from a position immediately above one response lever to a position at the top center of the front wall of the test chamber. This change reduced the accuracy of male rats less than the accuracy of female rats; prior exposure to PCB153 did not alter this effect in either sex. Later in training, accuracy in the SDT was quantified as P(hit), the proportion of signals accurately detected; and P(fa), the proportion of false reports of signals on trials with no signal. When constant trial timing was changed to variable trial timing, P(hit) was reduced and P(fa) was increased in all groups. The reduction in P(hit) was greater in males than in females, but did not depend on PCB exposure. Compared to controls, the increase in P(fa) was greater in both sexes of rats exposed to PCB at 60 mg/kg/day, and greater in female, but not male, rats exposed to PCB153 at 5 mg/kg/day. These data suggest that PCB153 may subtly impair attention and / or learning in rats, but that it is not obviously more neurotoxic than other PCBs previously tested, including PCB126, a non-ortho--substituted congener, and Aroclor 1254, a complex mixture of PCBs and other PAHs. (This abstract may not reflect EPA policy.)