Stewart IBN 9870382 Phenylethanolamine N-methyltransferase (PNMT) is the final enzyme required for synthesis of the stress hormone epinephrine. Recent studies indicate that the PNMT gene is expressed in mammalian lymphoid organs, such as spleen, thymus and lymph nodes, but it is unclear what types of cells in these organs produce PNMT and whether the PNMT in these areas has other functions in addition to synthesis of epinephrine. Similarly, PNMT and epinephrine are found in the brains of vertebrates, but the functions of epinephrine in the brain have never been clarified. The goals of the proposed project are to (1) identify cells that express the PNMT gene in the central nervous system and lymphoid tissues of rats and mice, (2) investigate the regulation of PNMT and epinephrine in these areas and (3) explore model systems for studying the function of epinephrine in these tissues. These studies will increase our understanding of the role of PNMT and epinephrine in both the nervous system and the immune system. Because epinephrine is present in the vertebrate brain and in immune cells of organisms as diverse as primates and molluscs, the findings will have broad implications for regulatory mechanisms in many species.