Towards a better preclinical model of PTSD: Characterizing animals with weak extinction, maladaptive stress responses and low plasma corticosterone
| Autor: | Clement Hamani, Mustansir Diwan, Roman Reznikov, José N. Nobrega |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Male
Elevated plus maze Conditioning Classical Poison control Physiology Extinction Psychological Developmental psychology Rats Sprague-Dawley Stress Disorders Post-Traumatic chemistry.chemical_compound Corticosterone medicine Animals Fear conditioning Maze Learning Biological Psychiatry Behavior Animal Novelty Fear social sciences Extinction (psychology) humanities Rats Disease Models Animal Psychiatry and Mental health chemistry Anxiety Conditioning medicine.symptom Psychology Locomotion Stress Psychological |
| Zdroj: | Journal of Psychiatric Research. 61:158-165 |
| ISSN: | 0022-3956 |
| Popis: | Most of the available preclinical models of PTSD have focused on isolated behavioural aspects and have not considered individual variations in response to stress. We employed behavioural criteria to identify and characterize a subpopulation of rats that present several features analogous to PTSD-like states after exposure to classical fear conditioning. Outbred Sprague-Dawley rats were segregated into weak- and strong-extinction groups on the basis of behavioural scores during extinction of conditioned fear responses. Animals were subsequently tested for anxiety-like behaviour in the open-field test (OFT), novelty suppressed feeding (NSF) and elevated plus maze (EPM). Baseline plasma corticosterone was measured prior to any behavioural manipulation. In a second experiment, rats underwent OFT, NSF and EPM prior to being subjected to fear conditioning to ascertain whether or not pre-stress levels of anxiety-like behaviours could predict extinction scores. We found that 25% of rats exhibit low extinction rates of conditioned fear, a feature that was associated with increased anxiety-like behaviour across multiple tests in comparison to rats showing strong extinction. In addition, weak-extinction animals showed low levels of corticosterone prior to fear conditioning, a variable that seemed to predict extinction recall scores. In a separate experiment, anxiety measures taken prior to fear conditioning were not predictive of a weak-extinction phenotype, suggesting that weak-extinction animals do not show detectable traits of anxiety in the absence of a stressful experience. These findings suggest that extinction impairment may be used to identify stress-vulnerable rats, thus providing a useful model for elucidating mechanisms and investigating potential treatments for PTSD. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect