Sex Differences in Contextual Extinction Learning After Single Binge-Like EtOH Exposure in Adolescent C57BL/6J Mice

Abstract

The relationship between chronic heavy drinking and post-traumatic stress disorder (PTSD) is well-documented; however, the impact of more common drinking patterns, such as a single episode leading to a blood alcohol concentration (BAC) of 0.09 g/dL (moderate intoxication), remains underexplored. Given the frequent co-occurrence of PTSD and alcohol misuse, it is essential to understand the biological and behavioral factors driving this comorbidity. We hypothesize that alcohols immediate sedative effects are coupled with the development of persistent molecular alcohol tolerance, which may disrupt fear extinction learning. To investigate this, we employed a Single Episode Ethanol (SEE) in-vivo exposure to mimic binge-like alcohol consumption over a 6-hour period, following contextual conditioning trials. Extinction trials were conducted 24 hours later to assess the effects on extinction learning. Our findings reveal a significant deficit in fear extinction learning in alcohol-treated adolescent male mice compared to saline-treated controls, with no such effects observed in female adolescent mice. These results suggest that even non-chronic alcohol exposure may contribute to the development of trauma- and stress-related disorders, such as PTSD, in males. Additionally, histological analysis revealed significant alterations in FKBP5, {beta}-catenin, and GSK-3{beta} levels in the hippocampus, striatum, and basolateral amygdala of alcohol-treated mice following extinction. The insights gained from this study could reshape our understanding of the risk factors for PTSD and open new avenues for prevention and treatment, targeting the molecular mechanisms that mediate alcohol tolerance. STATEMENT OF SIGNIFICANCEThis study investigates the impact of binge-like alcohol exposure on context extinction learning, aiming to identify previously unrecognized risks associated with this common drinking pattern and the development of trauma- and stress-related disorders, such as PTSD. Our findings reveal that binge-like alcohol exposure impairs extinction learning in male adolescent mice by disrupting molecular mechanisms within fear memory circuits, suggesting novel therapeutic and preventive targets. Dysregulated candidates include the canonical Wnt/{beta}-catenin signaling proteins, {beta}-catenin and GSK-3{beta}, along with FKBP5, a key player in glucocorticoid signaling and part of a gene network linked to PTSD. These alterations, found in the dorsal hippocampus (dHPC), basolateral amygdala (BLA), striatum, and nucleus accumbens (NAc) core and shell, may serve as promising targets for future pharmacological intervention.