Modern electrochemical and electroanalytical techniques are being used to probe the in vitro and in vivo behavior of neurochemical systems related to adrenergic neurotransmitters. The in vitro studies emphasize chemical studies of both catecholamines and neuropharmacological agents, providing new methods of analysis and leading to understanding of drug interactions in the CNS. The in vivo applications are utilizing micro electrodes for direct monitoring of electroactive species in living CNS tissue. It has already been established that these in situ electrodes can reliably monitor the release of dopamine and 5-hydroxytryptamine as neurotransmiters. We are pursuing this new brand of electrophysiology which emphasizes micro level current-voltage measurement.