Steroid hormones exert dynamic control over a wide variety of biological functions in mammals. An important goal is to gain an understanding of the mechanisms by which steroids, (e.g. estrogens, androgens, progestins) interact with the nervous system to alter physiological and behavioral functions. It is known that steroids can affect behavior by altering chemical communication between brain cells. Indeed Dr. Dohanich reports that estrogen influences the chemical signals produced by acetylcholine, a major muscarinic cholinergic neurotransmitter. He has shown that estrogen activates specific behaviors in females, in part, through the modulation of acetylcholine neurotransmission. Dr. Dohanich plans to extend his initial findings by determining the effects of cholinergic manipulations on a variety of steroid hormone regulated behaviors. In addition, he will investigate the role that various muscarinic receptors subtypes play in the regulation of these behaviors. Finally, Dr. Dohanich will determine the changes in cellular receptors for acetylcholine following hormonal manipulations that alter these specific behaviors. The results of this work will enhance our understanding of the role of neurotransmission in the regulation of mammalian behavior. This is important since the interplay between neurotransmitters and steroid hormones is a fundamental mechanisms that influences many functions in the central nervous system of mammals including humans. Consequently, this research has important implications for understanding the biological processes that underline steroid- dependent events ranging from reproduction to human mood states.
