Although gonadal hormones act on the brain to influence a variety of processes, it is unclear exactly how these hormones act on the brain to produce their effects. Recently, induction of the proto-oncogene c-fos has been used as a tool to identify individual neurons and areas of the brain which are activated by particular physiological stimuli. The present project proposes to adapt the technique of c-fos immunocytochemistry to examine which nuclei in the brain are activated during exposure to the ovarian hormones estrogen and progesterone and during sexual behavior in the female guinea pig. In addition, the techniques to double label cells for c-fos and a variety of neuropeptides will be developed so that it can be ascertained whether particular neuropeptides are contained in the cells which are activated by ovarian hormones and sexual behavior. This will give us further insights into exactly how and where these gonadal hormones may be exerting their effects and will provide the preliminary data to form the basis of a grant proposal which will examine whether the noradrenergic system and ovarian hormones interact at a particular subset of neurons to exert their facilitatory actions on female lordosis behavior.
