Hypothalamo‐pituitary axis dysfunction in animals that exhibit a maladaptive response to a traumatic stressor

Abstract

Post traumatic stress disorder (PTSD) often co‐exists with substance use disorders including alcohol abuse. Our lab utilizes predator odor exposure, an established model of traumatic stress, allowing rats to be divided into groups based on persistent avoidance an odor‐paired chamber, a phenotype similar to humans with PTSD. Preliminary studies in our lab show that avoider rats consume significantly more alcohol than non‐avoider rats and unstressed controls. Dysregulation in hypothalamo‐pituitary axis (HPA) function occurs in both PTSD patients and alcohol‐dependent individuals. We hypothesize that HPA dysregulation following exposure to a traumatic stressor contributes to increases in alcohol consumption in avoider rats. The purpose of this study was to examine HPA activity in avoider and non‐avoider rats following a traumatic stress. Male Wistar rats (300g) underwent a place conditioning procedure to assess avoidance of the odor‐paired chamber. Fifty percent of the rats exhibited avoidance of the odor‐paired chamber. Non‐avoider rats show an increase adrenocorticotropin releasing hormone (ACTH) post‐odor exposure compared to unstressed controls (769±133 vs. 1204±379pg/ml). ACTH levels are attenuated in avoider rats compared to non‐avoider (1204±379 vs. 879±85pg/ml; p=NS). Whether this contributes to the excessive drinking in avoider animals is unknown and the focus of current studies. This work was supported by NIH grant AA018400 (NWG).