The neural response of organisms to alcohol consumption involves extensive cell-cell communication, activation of signal transduction pathways and changes in gene transcription. The complexity of the response has hindered reaching basic mechanistic understandings of the critical events. Recently, advances in genetic analysis and technology allow the evaluation of the role of an individual gene in the response to alcohol consumption. Using genetic technology, it was found that mice lacking the ability to synthesize the neurotransmitter norepinephrine (NE) exhibit altered responses to ethanol administration. These mice have reduced preference for ethanol self-administration and are more sensitive to the sedative effects of ethanol, suggesting a role for NE in the response of the nervous system to ethanol. Unrelated studies found that treatment of neuroblastoma cell cultures with ethanol resulted in a specific elevation of mRNAs and proteins corresponding to two enzymes involved in the biosynthesis of NE, dopamine beta-hydroxylase (DBH which catalyzes the production of NE from dopamine, and tyrosine hydroxylase (TH), responsible for the formation of DOPA. The focus of this application is to further understand the cellular response to ethanol by identification and characterization of the components involved in transcriptional regulation of the DBH and TH genes. In addition, this proposal is designed to further explore the involvement of NE in the transcriptional adaptation to ethanol.
The specific aims are to: (1) Define the ethanol-responsive genetic regulatory elements of the rat TH and DBH genes, and the factors which bind to those elements. (2) Evaluate the importance of NE neurotransmission to alcohol responsiveness in vivo by comparing gene expression patterns in the amygdala, ventral tegmentum and nucleus accumbans between wild type and DBH deficient mice. (3) Characterize the response of the TH and DBH genes to acute and chronic ethanol administration in the mouse CNS. The results of these experiments will further our understanding of the role NE synthesis and neurotransmission in the cellular adaptation to alcohol treatment.
