Compulsive consumption of alcohol is a disease state that affects otherwise healthy individuals. The GDNF signaling pathway plays a role in the regulation of alcohol consumption. The proposed research has two broad aims: 1) to determine the downstream effectors and molecular mechanisms that underlie this action of GDNF, and 2) to determine whether the GDNF signaling pathway is part of a homeostatic mechanism by which alcohol consumption is negatively regulated. Firstly, the actions of GDNF signaling on the phosphorylation of two candidate proteins, Kv4.3 and Synapsin I, will be investigated. Use of in vitro model systems, including an immortalized cell line and primary neuron cultures, will be used to biochemically determine the extent of protein phosphorylation. Because the neurotransmitter dopamine plays a major role in the consumption of alcohol, the effects of GDNF, as well as the GDNF-mediated phosphorylation of these protein targets, on dopamine release will be investigated. siRNA knockdown of the Kv4.3 and/or Synapsin I proteins, along with high-performance liquid chromatography (HPLC) to quantify dopamine release, will be used to determine whether either candidate effector functions in GDNF-mediated dopamine release. Secondly, the effect of ethanol on the upregulation of GDNF and subsequent activation of its signaling pathway will be further characterized in both in vitro and in vivo models. RT-PCR and biochemical techniques will be used to support this aim. Understanding the effect of alcohol consumption on GDNF signaling, as well as the effects of GDNF on alcohol consumption, will contribute to the understanding of the neurobiology of alcohol addiction, and the development of efficacious therapies to alleviate the alcoholic's disease state. Relevance: Alcoholism is a widespread and costly societal problem. Identifying novel molecular targets that may be used to develop drug therapies that can regulate alcohol consumption is a worthwhile pursuit. This research will contribute to the current knowledge base for the understanding and treatment of this and other drug addictions. ? ? ?
