Acute exposure of rats to a severe stressor alters the circadian pattern of corticosterone and sensitizes to a novel stressor : Relationship to pre-stress individual differences in resting corticosterone levels
Belda, Xavier (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Fuentes, Silvia (Universitat Autònoma de Barcelona. Departament de Psicobiologia i de Metodologia de Ciències de la Salut)
Labad, Javier (Universitat Autònoma de Barcelona. Departament de Psiquiatria i de Medicina Legal)
Nadal i Alemany, Roser (Universitat Autònoma de Barcelona. Departament de Psicobiologia i de Metodologia de Ciències de la Salut)
Armario Garcia, Antonio (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Universitat Autònoma de Barcelona. Institut de Neurociències

Date:	2020
Abstract:	Traumatic events have been proposed to be associated with hypo-activity of the hypothalamic-pituitary-adrenal (HPA) axis, but data in animal models exposed to severe stressors are controversial and have important methodological concerns. Individual differences in resting or stress levels of corticosterone might explain some of the inconsistencies. We then studied this issue in male rats exposed to 2 h immobilization on boards (IMO), a severe stressor. Thirty-six rats were blood sampled under resting conditions four times a day on three non-consecutive days. Then, they were assigned to control (n = 14) or IMO (n = 22) to study the HPA response to IMO, the stressor-induced alterations in the circadian pattern of corticosterone (CPCORT), and the behavioral and HPA responsiveness to an open-field. Individual differences in pre-IMO resting corticosterone were inconsistent, but averaging data markedly improved consistency. The CPCORT was markedly altered on day 1 post-IMO (higher trough and lower peak levels), less altered on day 3 and apparently normal on day 7. Importantly, when rats were classified in low and high resting corticosterone groups (LCORT and HCORT, respectively), on the basis of the area under the curve (AUC) of the averaged pre-IMO data, AUC differences between LCORT and HCORT groups were maintained in controls but disappeared in IMO rats during the post-IMO week. Open-field hypo-activity and corticosterone sensitization were similar in LCORT and HCORT groups nine days after IMO. A single IMO exposure causes long-lasting HPA alterations, some of them dependent on pre-stress resting corticosterone levels, with no evidence for post-IMO resting corticosterone hypo-activity.
Grants:	Agència de Gestió d'Ajuts Universitaris i de Recerca SGR2017-457 Agencia Estatal de Investigación SAF2017-83430-R
Note:	altres ajuts: Generalitat de Catalunya. Departament de Salut, SLT006/17/00012; 2015FEDER7S-20IU16-001945
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Hypothalamic-pituitary-adrenal axis ; PTSD ; Immobilization stress ; Individual differences ; Aggregated data ; Circadian rhythm ; Hypercorticosteronemia ; Hypocorticosteronemia
Published in:	Hormones and Behavior, Vol. 126 (november 2020) , p. 104865, ISSN 1095-6867

DOI: 10.1016/j.yhbeh.2020.104865

30 p, 3.7 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Health sciences and biosciences > Institut de Neurociències (INc)
Articles > Research articles
Articles > Published articles