Alcohol Dependence in Mice: A Cocktail of Change in Region-specific mRNA Concentration and Protein Amount

Alcohol dependence poses great challenges against addressing Alcohol Use Disorders (AUD) by increasing tolerance to the drug’s adverse effects and inducing distressing withdrawal symptoms. With chronic alcohol use, the brain adjusts to recurrent excessive inhibitory signaling through physiological changes to upregulate excitatory neurotransmission. In particular, glutamate-detecting α-amino-3-hydroxy-5-methyl-4 isoxazolepropionic acid receptor (AMPAR) increases in synaptic density and activity upon prolonged alcohol use by an unknown mechanism. The shift towards glutamate signaling is indicative of neuroplasticity and anxiety-like symptoms that favor elevated alcohol drinking patterns. To identify the mechanism as to which dependence develops through the AMPAR pathway, C57BL/6J mice underwent the wellestablished Chronic Intermittent Ethanol (CIE) exposure to induce physiological responses similar to those observed in alcohol dependence in humans. Then, through qRT-PCR, gene expression of AMPAR pathway components associated with alcohol drinking behavior (GluA1,TARP-8, and PSD-95) were observed in brain regions (Prefrontal Cortex, Amygdala, Insular Cortex, and Nucleus Accumbens) particularly sensitive to excitatory signaling and interconnected in the reward pathway. Gene expression changes were then verified with relative protein concentrations to ensure processing of mRNA for activity. Significant changes indicate modulation of components of interest, which project onto the Nucleus Accumbens to retain neural homeostasis. In relation to protein concentration, further experimentation, such as varying decapitation time, is necessary to account for additional cellular and biochemical considerations such as mRNA and protein processing, time in between and during transcription and translation, and reaction with the inter- and intracellular environment. Follow up studies to this experiment will provide clearer insight into molecular targets for pharmacological AUD interventions.Bachelor of Art