PCBs alter the developing brain which may lead to alterations in human cognition. This is a concern for many Akwesasne Mohawk women who had elevated body concentrations of PCBs and whose children were exposed during gestation and through breast feeding. Thus, it is important to understand the mechanism by which PCBs may induce cognitive and physical deficits in these children.
For this purpose, we will determine the neurochemical, neurobehavioral, and endocrine effects of in utero and lactational exposure of the laboratory rat to individual PCB congeners. These congeners were selected because they alter neurochemical and second messenger systems and the development of key endocrine systems including thyroid and estrogens- all of which are important for normal brain development.
During the first year of study, biogenic amine concentrations were measured in brain slices of rats exposed in vitro to each congener to determine which congeners directly affect neurochemical function.
In the remaining years of the study, pregnant rats (dams) will be exposed to these congeners during gestation and lactation. The developing rats will be assayed for PCB induced alterations in endocrine status and these changes will be correlated with neurochemical and neurobehavioral changes. Animals will also be exposed to pharmacological agents during development to determine whether neurochemical and endocrine changes, seen after congener exposure, are due to selective alterations in these specific systems. Finally, the study will determine the effects of developmental exposure to PCBs on cognitive function. These studies, using a number of prototypical PCB congeners, will determine which congeners directly affect neurotransmitter development, indirectly affect endocrine and brain development, and the behavioral consequences of perinatal exposure.
