Brain responses to chronic social defeat stress: Effects on regional oxidative metabolism as a function of a hedonic trait, and gene expression in susceptible and resilient rats

Kanarik, Margus; Alttoa, Aet; Matrov, Denis; Kõiv, Kadri; Sharp, Trevor; Panksepp, Jaak; Harro, Jaanus

doi:10.1016/j.euroneuro.2010.06.015

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Volume 21, Issue 1 , Pages 92-107, January 2011

Brain responses to chronic social defeat stress: Effects on regional oxidative metabolism as a function of a hedonic trait, and gene expression in susceptible and resilient rats

Margus Kanarik
- Department of Psychology, Estonian Centre of Behavioural and Health Sciences, University of Tartu, Tiigi 78, 50410 Tartu, Estonia
Aet Alttoa
- Department of Psychology, Estonian Centre of Behavioural and Health Sciences, University of Tartu, Tiigi 78, 50410 Tartu, Estonia
Denis Matrov
- Department of Psychology, Estonian Centre of Behavioural and Health Sciences, University of Tartu, Tiigi 78, 50410 Tartu, Estonia
Kadri Kõiv
- Department of Psychology, Estonian Centre of Behavioural and Health Sciences, University of Tartu, Tiigi 78, 50410 Tartu, Estonia
Trevor Sharp
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
Jaak Panksepp
- Department of VCAPP, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6520, USA
Jaanus Harro
- Department of Psychology, Estonian Centre of Behavioural and Health Sciences, University of Tartu, Tiigi 78, 50410 Tartu, Estonia
- Corresponding author. Tel.: +372 7 375911; fax: +372 7375900.

Received 29 March 2010; received in revised form 21 June 2010; accepted 27 June 2010. published online 26 July 2010.

Abstract

Chronic social defeat stress, a depression model in rats, reduced struggling in the forced swimming test dependent on a hedonic trait-stressed rats with high sucrose intake struggled less. Social defeat reduced brain regional energy metabolism, and this effect was also more pronounced in rats with high sucrose intake. A number of changes in gene expression were identified after social defeat stress, most notably the down-regulation of Gsk3b and Map1b. The majority of differences were between stress-susceptible and resilient rats. Conclusively, correlates of inter-individual differences in stress resilience can be identified both at gene expression and oxidative metabolism levels.

Keywords: Chronic social defeat stress, Oxidative energy metabolism, Cytochrome oxidase histochemistry, Animal models of depression, Sucrose intake, Genome-wide expression profiling