Neurobehavioral Assessments of Rats Perinatally Exposed to a Commercial Mixture of Polychlorinated Biphenyls

Because of behavioral deficits associated with gestational exposure to PCBs in children, we sought to quantify neurobehavioral effects of perinatal exposure to Aroclor 1254(R) (A1254), a commercial mixture of PCBs, in rats. Pregnant Long-Evans rats were fed A1254 at doses of 0, 1.0, or 6.0 mg/kg/day throughout gestation and nursing. The growth and behavior of their male and female offspring were assessed both during development and as adults, using a variety of behavioral tests that included a neurobehavioral screening battery (functional observational battery [FOB] and automated tests of locomotor activity), habituation of motor activity, acquisition of a visual discrimination, and performance of a visual signal-detection task. During the suckling period, A1254 at 6 mg/kg reduced survival and body weight gain of offspring of both sexes; however, locomotor activity was unaffected, and only small and transient changes in other measures were evident. In adulthood, perinatal exposure to A1254 did not affect habituation of locomotor activity, acquisition of the visual discrimination, or sustained attention. Rats performing the signal-detection task were challenged with cocaine (0, 1.25, 2.5, 5.0 mg/kg) and haloperidol (0, 0.003, 0.010, 0.030 mg/kg) to probe the integrity of dopaminergic systems in the central nervous system (CNS). A1254 did not alter the impairment of attention caused by haloperidol. Cocaine reduced false alarms more in controls than in rats exposed to A1254, but the effect was not clearly related to the dose of A1254. Perinatal exposure to this commercial PCB mixture had very little effect on these tests of behavior during development and in adulthood.