| Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that remain in the environment today even after their production was banned in the United States in the 1970s. While many studies have examined the effects of PCBs on a variety of behaviors and developmental outcomes, the effects of the contaminants on maternal behavior have been largely ignored. Those that have evaluated maternal behavior after gestational exposure to PCB used the traditional paradigm in which a dam is treated while she is pregnant and the resulting maternal behavior is evaluated. With this approach, it is impossible to distinguish between effects on maternal behavior that are the result of direct actions on the dams' endocrine and/or nervous systems, from those that stem from indirect effects mediated by changes in the physical and behavioral profiles of the exposed litter. In this dissertation, I examined the effects of different doses of the dioxin-like PCB congener 3, 4, 3', 4'-tetrachlorobiphenyl (PCB 77) on maternal behavior in rats using a cross-fostering paradigm to gain insights about the contributions of direct and indirect effects of PCB 77 exposure on maternal behavior. I also examined the effects of the toxin on offspring partner preference and sexual behavior.; Various components of maternal behavior were affected when dams were treated with a dose of 2 mg/kg b.w. on gestation day (GD) 6--18. Some of the effects on maternal behavior can be ascribed to prenatal exposure of the litters to the PCB, while other effects appear to be due to both direct effects of the PCB on the dams and effects mediated by changes in the offspring.; A second experiment employed a dose of 3 mg/kg to determine how an intermediate dose of PCB 77 affects maternal behavior and to expand the behavioral analysis. The results from this experiment confirm that exposing dams to PCB during gestation alters the care they provide to their litters, and that many of the affected behaviors appear to be the result of dams rearing prenatally PCB-exposed pups instead of being due to the treatment the dams received while pregnant.; Finally, we examined the sexual behavior and partner preference of offspring that were exposed to PCB pre- and/or postnatally. While PCB exposure did not affect male or female sexual behavior, it did alter the display of partner preference behavior. These effects were more salient in the females than the males.; This dissertation also addresses the traditional experimental paradigm that is often used, in which treatment of the dam is simply considered an avenue through which toxins can be delivered to the developing embryo without taking into consideration any possible alterations in the dams' behavior. Since such exposure is not specific to the pups the effects of the contaminant on the dam must be evaluated in terms of its impact on the offspring. |
