In female rats, the gonadal hormones estrogen and progesterone modulate activity of the neurotransmitter, dopamine (DA), in the brain. Experiments in this laboratory have been directed at defining the mechanisms mediating the effect of estrogen in the brain, as well as attempting to determine the functional role of this phenomena in the natural behavior of the rat. With the latter in mind, we find that DA in one particular area of the brain, the striatum, is important for specific aspects of the female rat reproductive behavior. The mechanism(s) mediating the effects of the gonadal hormones on the striatum appears to be different from those mediating the effects of estrogen and progesterone at intracellular (traditional) estrogen receptors. Research from my laboratory has repeatedly demonstrated that estrogen acts in the striatum through a novel mechanism. There are two key questions about the role of gonadal hormones in the modulation of DA activity in the female rat that the experiments in this proposal will address: 1) What are the mechanism(s) mediating the effects of estrogen on the striatum?; and 2) What role(s) of the striatum, and of DA release, in reproductive behavior in the female rat? The involvement of the gonadal steroid hormones in the modulation of striatal DA activity is important for our understanding of the basic processes of neuroendocrinology as well as our understanding of the functions of the basal ganglia. Identifying novel mechanisms through which steroid hormones act in the brain has important implications for our understanding of where, how, and when these hormones affect the brain activity and behavior. Finally, these experiments will help us to understand how these hormones modulate behavior in the female rat.
