The experiments in this proposal focus on the effects of gonadal steroids and sensory stimuli on noradrenergic (NE) transmission in brain regions that mediate reproductive behavior in female rats. Steroid-regulated NE input into both the ventromedial hypothalamus (VMH) and medial preoptic area (MPOA) may help coordinate reproductive function and may regulate other neurotransmitters known to influence reproductive behavior within these brain regions. The objectives of these experiments are 1) to determine which aspects of sensory input associated with reproductive behavior (chemosensory or somatosensory) contribute to hypothalamic NE release; 2) to determine the steroid dependence and stimulus dependence of NE transmission in the MPOA. in vivo brain microdialysis will be used in awake, behaving animals to accomplish goals l and 2; and 3) to determine the role of NE and gonadal steroids in regulating GABA release in the POA and hypothalamus, and to determine which NE receptor subtype mediates any interaction between NE and GABA. This will be achieved using in vitro release studies on brain tissue slices using steroid treatments and pharmacological manipulations. This research project is aimed at determining NE and GABA interactions, sensory influences on NE release, and steroid influences on NE release. These experiments have implications for understanding the mechanisms underlying human reproduction and affective disorders such as depression, since both NE and GABA and interactions between steroids and these neurotransmitters are involved in these phenomena.
