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Predator odor exposure facilitates acquisition of a leverpress avoidance response in rats

Authors Francis X Brennan, Kevin D Beck, Richard J Servatius

Published 15 March 2006 Volume 2006:2(1) Pages 65—69

Francis X Brennan1,2, Kevin D Beck3,4, Richard J Servatius3,4
1Medical Research (151), VA Medical Center, Philadelphia, PA, USA; 2Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA; 3Neurobehavioral Research Laboratory, VA Medical Center, East Orange, NJ, USA; 4Department of Neuroscience, New Jersey Medical School, Newark, NJ, USA
Abstract: We have previously reported that prior exposure to inescapable tailshock stress increased avoidance responding 24 hours later. We argued previously that this might model the avoidance behavior characteristic of post-traumatic stress disorder (PTSD). The current experiment was conducted to determine whether a more ethologically relevant stressor would produce similar effects on avoidance responding. Therefore, rats were restrained for 2 hours and exposed to trimethylthiazoline (TMT), a component of fox feces, restrained only, or served as home cage controls. Twenty-four hours later, subjects received a 4-hour escape–avoidance session. Animals exposed to TMT made more escape responses overall, and made more avoidance responses than the other two groups by the 4th hour of the session. Differences between the TMT-exposed animals and restraint alone could not be explained by differences in corticosterone (CORT) levels. Results are discussed in terms of the possible neural changes induced by TMT exposure and the relationship to the behavioral aspects of PTSD or acute stress.
Keywords: stress, escape–avoidance, coping, trimethylthiazoline, learning

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