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The immediate early gene, activity-regulated cytoskeleton-associated protein (Arc), has been implicated in synaptic plasticity. However, the role of Arc in alcoholism is unknown. Here, we report that the anxiolytic effects of acute ethanol were associated with increased brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (trkB) expression, increased phosphorylation of extracellular signal-regulated kinases 1/2 (Erk1/2), Elk-1, and cAMP responsive element-binding protein (CREB), increased Arc expression, and increased dendritic spine density (DSD) in both the central amygdala (CeA) and medial amygdala (MeA) but not in the basolateral amygdala (BLA) of rats. Conversely, the anxiogenic effects of withdrawal after long-term ethanol exposure were associated with decreased BDNF and trkB expression, decreased phosphorylation of Erk1/2, Elk-1, and CREB, decreased Arc expression, and decreased DSD in both the CeA and MeA but not in the BLA of rats. We also showed that BDNF infusion into the CeA normalized phosphorylation of Erk1/2, Elk-1, and CREB, and normalized Arc expression, thereby protecting against the onset of ethanol withdrawal-related anxiety. We further demonstrated that arresting Arc expression in the CeA decreased DSD, thereby increasing anxiety-like and alcohol-drinking behaviors in control rats. These results revealed that BDNF-Arc signaling and the associated DSD in the CeA, and possibly in the MeA, may be involved in the molecular processes of alcohol dependence and comorbidity of anxiety and alcohol-drinking behaviors. [ABSTRACT FROM AUTHOR]

The cAMP response element-binding protein (CREB) gene transcription factor has been shown to play a role in the synaptic plasticity associated with drug addictive behaviors; however, the causal role of the CREB gene in alcohol-drinking behaviors is unknown. The present investigation evaluated alcohol-drinking behaviors in mice that are haplodeficient in CREB as a result of targeted CREB (α and Δ) gene disruption. It was found that CREB-haplodeficient (+/-) mice have higher preference for ethanol but not for sucrose solution than wild-type (+/+) littermates. The functional aspects of the CREB gene transcription factor were also investigated by measuring the protein levels of phosphorylated CREB (p-CREB) and the expression of cAMP- inducible genes such as neuropeptide Y (NPY) and brain-derived neurotrophic factor (BDNF). Deletion of the CREB (α and Δ) gene significantly decreases total CREB, p-CREB levels and the expression of NPY and BDNF in the brain structures of CREB-deficient (+/-) mice. It was also found that CREB-deficient (+/-) mice displayed more anxiety-like behaviors and that acute ethanol exposure produced anxiolytic effects and significantly increased protein levels of p-CREB and NPY in the central and medial but not in the basolateral amygdala of wild-type mice, but these effects are attenuated in CREB-deficient mice compared with wild-type mice. These results provide the first direct evidence that a haplodeficiency of the CREB gene is associated with increased alcohol-drinking behaviors. Furthermore, alcohol drinking and anxiety-like behaviors in CREB-haplodeficient mice may possibly be related to decreased expression of NPY and BDNF in the brains of these mice. [ABSTRACT FROM AUTHOR]