Social defeat stress produces prolonged alterations in acoustic startle and body weight gain in male Long Evans rats.

Individuals exposed to psychological stressors may experience a long-term resetting of behavioral and neuroendocrine aspects of their "stress response" so that they either hyper or hypo-respond to subsequent stressors. These effects of psychological or traumatic stressors may be mimicked in rats using the resident-intruder model of social defeat. The social defeat model has been characterized to model aspects of the physiology and behavior associated with anxiety and depression. The objective of this study was to determine if behaviors elicited following repeated social defeat can also reflect aspects of ethologically relevant stresses associated with existing post traumatic stress disorder (PTSD) models. Socially defeated rats displayed weight loss and an enhanced and prolonged response to acoustic startle which was displayed for up to 10days following repeated social defeat. These data indicate that the severe stress of social defeat can produce physiologic and behavioral outcomes which may reflect aspects of traumatic psychosocial stress. Copyright 2009 Elsevier Ltd. All rights reserved.