We propose to study, at the molecular biological level, the regulatory mechanisms governing the enzyme choline acetyltransferase (CAT) which catalyzes the synthesis of the neurotransmitter, acetylcholine. We shall isolate and translate mRNA in vitro to obtain CAT, which will be detected using immunoprecipitation techniques. In order to obtain monospecific antibodies directed against CAT, we will establish cell lines secreting monoclonal antibodies against CAT. With these monoclonal antibodies we shall (a) investigate the biochemical mechanisms of CAT induction and activation produced by drugs, nerve injury and stimulation as well as during growth and development; (b) determine the rates of synthesis and degradation of CAT in the CNS and, as a simple system, in cultured cell lines of pheochromocytoma; and (c) purify mRNA coding for CAT to determine in vitro whether translational activity is involved in the mechanisms which alter CAT activity.