Measurement and Regulation of Central Noradrenergic Neurotransmission

Abstract : Over the period of the AFOSR grant we have made significant progress in clarifying the relationship between the noradrenergic system and IEG expression in the brain. A series of studies has been performed in which the effects of activation of the noradrenergic system by drugs or stress on activation of the IEG response was examined. Results strongly suggest that the noradrenergic system is involved in the activation of IEGs caused by physiological as well as pharmacological agents. Whether this is the only neuronal system involved is not yet clear as stress, yohimbine and propranolol are known to affect other neurotransmitters and their receptors in the brain. This problem will be addressed in future research. In conjunction with our biochemical studies of noradrenergic neurotransmission we have also sought to identify the postsynaptic cells in which these biochemical events occur so as to facilitate studies of long term changes caused by stress. We have made substantial progress in this area and have obtained evidence that there are 2 separate target cells, a glial cell in which cyclic AMP is synthesized in response to beta receptor activation and a neuronal cell in which the immediate early genes are produced again in response to beta receptor activation.