Sex differences in the behavioural and hypothalamic-pituitary-adrenal response to contextual fear conditioning in rats
Daviu Abant, Núria (Universitat Autònoma de Barcelona. Institut de Neurociències)
Andero Galí, Raül (Universitat Autònoma de Barcelona. Institut de Neurociències)
Armario Garcia, Antonio (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Nadal i Alemany, Roser (Universitat Autònoma de Barcelona. Institut de Neurociències)

Data:	2014
Resum:	In recent years, special attention is being paid to sex differences in susceptibility to disease. In this regard, there is evidence that male rats present higher levels of both cued and contextual fear conditioning than females. However, little is known about the concomitant hypothalamic-pituitary-adrenal (HPA) axis response to those situations which is critical in emotional memories. Here, we studied the behavioural and HPA responses of male and female Wistar rats to context fear conditioning using electric footshock as the aversive stimulus. Fear-conditioned rats showed a much greater ACTH and corticosterone response than those merely exposed to the fear conditioning chamber without receiving shocks. Moreover, males presented higher levels of freezing whereas HPA axis response was greater in females. Accordingly, during the fear extinction tests, female rats consistently showed less freezing and higher extinction rate, but greater HPA activation than males. Exposure to an open-field resulted in lower activity/exploration in fear-conditioned males, but not females, suggesting greater conditioned cognitive generalization in males than females. It can be concluded that important sex differences in fear conditioning are observed in both freezing and HPA activation, but the two set of variables are affected in the opposite direction: enhanced behavioural impact in males, but enhanced HPA responsiveness in females. Thus, the role of sex differences on fear-related stimuli may depend on the variables chosen to evaluate it, the greater responsiveness of the HPA axis in females perhaps being an important factor to be further explored.
Ajuts:	Ministerio de Economía y Competitividad 2011-021 Ministerio de Economía y Competitividad SAF2011-28313 Instituto de Salud Carlos III RD12/0028/0014 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1020
Nota:	This is the author's version of a work that was accepted for publication in Hormones and behavior. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Hormones and behavior, Vol. 66 No. 5 (Nov. 2014), p. 713-723
Nota:	Altres ajuts: MSSSI/RD2012/0028/0014
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	ACTH ; Hormona alliberadora de corticotropina ; Anxiety ; Ansietat ; Corticosterone ; Corticosterona ; HPA Axis ; Hypothalamic-pituitary-adrenal axis ; Eix hipotalàmic-pituïtari-adrenal ; Sex Differences ; Diferències entre sexes
Publicat a:	Hormones and behavior, Vol. 66 Núm. 5 (Nov. 2014) , p. 713-723, ISSN 0018-506X

DOI: 10.1016/j.yhbeh.2014.09.015

Post-print 35 p, 995.9 KB

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