title: Predator-scent stress, ethanol consumption and the opioid system in an animal model of PTSD.
abstract: Emerging literature points to stress exposure as a potential contributor to the development of alcohol abuse, but animal models have yielded inconsistent results. Converging experimental data indicate that the endogenous opioid system modulates alcohol consumption and stress regulation. The aim of the present study is to examine the interplay between stress exposure, behavioral stress responses, ethanol (EtOH) consumption and the endogenous opioid system in an animal model of posttraumatic stress disorder. Rats were exposed to stress and then tested in a two-bottle free choice (TBC) assay or in a conditioned place preference paradigm. In some experiments, the endogenous opioid system was pharmacologically manipulated prior to stress exposure. The behavioral outcomes of stress exposure were assessed in an elevated plus-maze, with the acoustic startle response, and by monitoring the freezing response to trauma reminder. Immunoreactivity of phosphorylated opioid receptors in hippocampal subregions was also measured. Stress significantly increased the consumption of EtOH in the TBC assay. The severity of the behavioral response to stress was associated with EtOH consumption, cue-triggered freezing response to a trauma reminder, and endogenous levels of phosphorylated opioid receptors in the hippocampus. Pharmacologically manipulating the endogenous opioid system prior to stress exposure attenuated trauma cue-triggered freezing responses and blocked predator scent stress-induced potentiation of EtOH consumption. These data demonstrate a stress-induced potentiation of EtOH self-administration and reveal a clear association between individual patterns of the behavioral response to stress and alcohol preference, while indicating a role for the endogenous opioid system in the neurobiological response to stress.
authors.affiliation: Ben-Gurion University of the Negev, Department of Psychology, Beer Sheva, Israel; Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Hadar
authors.initials: H
authors.lastname: Manjoch
authors.affiliation: Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Ella
authors.initials: E
authors.lastname: Vainer
authors.affiliation: Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Matar
authors.affiliation: Headache Clinic, Department of Neurology, Soroka Medical Center, Ben-Gurion University of the Negev Beer- Sheva, Israel.
authors.forename: Gal
authors.initials: G
authors.lastname: Ifergane
authors.affiliation: Division of Psychiatry, The State of Israel Ministry of Health, The Chaim Sheba Medical Center, Sackler Medical School, Tel-Aviv University, Tel Hashomer, Israel.
authors.forename: Joseph
authors.initials: J
authors.lastname: Zohar
authors.affiliation: Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
authors.forename: Zeev
authors.initials: Z
authors.lastname: Kaplan
authors.affiliation: Ben-Gurion University of the Negev, Department of Psychology, Beer Sheva, Israel; Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel. Electronic address: hagitc@bgu.ac.il.
authors.forename: Hagit
authors.initials: H
authors.lastname: Cohen
mesh_terms: D000701:Analgesics, Opioid / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002755:Choice Behavior / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D004195:Disease Models, Animal; D000431:Ethanol / Q000378:metabolism* / Q000494:pharmacology; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects / Q000502:physiology; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017450:Receptors, Opioid, mu / Q000378:metabolism; D013313:Stress Disorders, Post-Traumatic / Q000150:complications*; D013315:Stress, Psychological / Q000503:physiopathology*
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D009294:Narcotics; D017450:Receptors, Opioid, mu; D009270:Naloxone; D000431:Ethanol; D009020:Morphine
keywords: Alcohol consumption; Animal model; Morphine; Naloxone; Opioid system; Post-traumatic stress disorder