Electrophysiology of alcohol in extended amygdala

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DESCRIPTION (provided by applicant): This project is based on behavioral findings that the central amygdala nucleus (CeA) and locus coeruleus (LC) are key brain areas involved in stress reactions and the reinforcing properties of abused drugs, and that these behaviors may involve several transmitters (GABA, glutamate, norepinephrine) and neuropeptides (CRF, opioids and galanin). Both regions are implicated in motivated behaviors and anxiety states, and we hypothesize that these same neurochemical systems within the CeA and LC are involved in the excessive ethanol drinking seen in dependent animals. Therefore, we propose several sets of experiments: 1) T assess the role of CRF receptors in excessive drinking, by comparing the CeA cellular and network function in brain slices from control and excessively drinking mice (WID model) mice, with respect to the ethanol augmentation of GABAergic IPSCs or inhibition of glutamatergic EPSPs, combined with cytochemical localization of CRF and CRF receptors. 2) To determine the role of kappa opiate receptors (KORs) in excessive drinking, for comparison to our mu and delta receptor data, by examining CeA cellular function in brain slices from WID mice with a knockout (KO) for brain KORs. 3) To determine the role of galanin and its receptors in excessive drinking, by examining CeA and LC cellular in slices from WID mice and those with KOs for brain Gall and Gal2 receptors and with galanin over-expression, and by neurochemical and molecular biological measures in CeA and LC neurons. 4) To determine the effects on the largest WIDinduced changes from the results of Specific Aims 1-3, in the HDID mice selectively bred by the Crabbe and Finn groups for high drinking in the dark versus their controls, and for SHAG vs.SLAG lines, selected for scheduled high and low alcohol consumption. The electrophysiological studies will use CeA and LC brain slices and involve standard intracellular and whole-cell clamp methods. We will use a battery of measures to assess the pre- versus postsynaptic sites of action of ethanol and peptide effects. RIA, real-time PCR and receptor binding studies will be used in the galanin studies. This project should provide important new information on the possible squeal of ethanol intoxication at the cellular level, and, by comparisons of ethanol and peptide actions in control, excessively drinking, and knockout models, will also provide clues as to the synaptic, cellular and ion channel correlates of ethanol dependence.