title: Exercise Enhances the Behavioral Responses to Acute Stress in an Animal Model of PTSD.
abstract: BACKGROUND
  This study examined the effects of endurance exercise on the behavioral response to stress and patterns of brain-derived neurotrophic factor (BDNF), neuropeptide Y (NPY), and δ-opioid receptor (phospho-DOR) expression in the hippocampus.
  
  
  METHODS
  Animals ran on a treadmill at 15 m·min, 5 min·d gradually increasing to 20 min·d, 5 d·wk for 6 wk. After training, one group of animals was exposed to a predator scent stress (PSS) protocol for 10 min. Outcome measurements included behavior in an elevated plus-maze (EPM) and acoustic startle response (ASR) 7 d after exposure to stress. Immunohistochemical technique was used to detect the expression of the BDNF, NPY, and phospho-DOR in the hippocampus 8 d after exposure.
  
  
  RESULTS
  Sedentary animals exposed to PSS were observed to have a greater incidence of extreme behavior responses including higher anxiety, less total activity in the EPM, and greater amplitude in the ASR than unexposed and/or trained animals. Exercise-trained animals exposed to PSS developed a resiliency to the stress, reflected by significantly greater total activity in the EPM, reduced anxiety, and reduced ASR compared to the sedentary, exposed animals. Exercise in the absence of stress significantly elevated the expression of BDNF and phospho-DOR, whereas exposure to PSS resulted in a significant decline in the expression of NPY, BDNF, and phospho-DOR. Trained animals that were exposed maintained expression of BDNF, NPY, and phospho-DOR in most subregions of the hippocampus.
  
  
  CONCLUSIONS
  Results indicated that endurance training provided a mechanism to promote resilience and/or recovery from stress. In addition, exercise increased expression of BDNF, NPY, and DOR signaling in the hippocampus that was associated with the greater resiliency seen in the trained animals.
authors.affiliation: 1Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida, Orlando, FL; 2Israel Defense Force, Medical Corps, Tel Hashomer, ISRAEL; 3Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Faculty of Health Sciences, Division of Psychiatry, Ben-Gurion University of the Negev, Beer-Sheva, ISRAEL; and 4The State of Israel Ministry of Health, The Chaim Sheba Medical Center, Division of Psychiatry, Ramat-Gan, Israel, Sackler Medical School, Tel-Aviv University, ISRAEL.
authors.forename: Jay R
authors.initials: JR
authors.lastname: Hoffman
authors.forename: Ishay
authors.initials: I
authors.lastname: Ostfeld
authors.forename: Zeev
authors.initials: Z
authors.lastname: Kaplan
authors.forename: Joseph
authors.initials: J
authors.lastname: Zohar
authors.forename: Hagit
authors.initials: H
authors.lastname: Cohen
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D004195:Disease Models, Animal; D015444:Exercise / Q000502:physiology / Q000523:psychology*; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D008297:Male; D018782:Maze Learning; D009478:Neuropeptide Y / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000378:metabolism; D013216:Reflex, Startle; D013313:Stress Disorders, Post-Traumatic / Q000378:metabolism / Q000523:psychology*; D013315:Stress, Psychological
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D009478:Neuropeptide Y; D017465:Receptors, Opioid, delta