Circadian arrhythmia dysregulates emotional behaviors in aged Siberian hamsters

Prendergast, B. J., Onishi, K. G., Patel, P. N. and Stevenson, T. J. (2013) Circadian arrhythmia dysregulates emotional behaviors in aged Siberian hamsters. Behavioural Brain Research, 261, pp. 146-157. (doi: 10.1016/j.bbr.2013.12.010) (PMID:24333374) (PMCID:PMC4343037)

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Abstract

Emotional behaviors are influenced by the circadian timing system. Circadian disruptions are associated with depressive-like symptoms in clinical and preclinical populations. Circadian rhythm robustness declines markedly with aging and may contribute to susceptibility to emotional dysregulation in aged individuals. The present experiments used a model of chronic circadian arrhythmia generated noninvasively, via a series of circadian-disruptive light treatments, to investigate interactions between circadian desynchrony and aging on depressive- and anxiety-like behaviors, and on limbic neuroinflammatory gene expression that has been linked with emotionality. We also examined whether a social manipulation (group housing) would attenuate effects of arrhythmia on emotionality. In aged (14–18 months of age) male Siberian hamsters, circadian arrhythmia increased behavioral despair and decreased social motivation, but decreased exploratory anxiety. These effects were not evident in younger (5–9 months of age) hamsters. Social housing (3–5 hamsters/cage) abolished the effects of circadian arrhythmia on emotionality. Circadian arrhythmia alone was without effect on hippocampal or cortical interleukin-1β (IL-1β) and indoleamine 2,3-dioxygenase (Ido) mRNA expression in aged hamsters, but social housing decreased hippocampal IL-1β and Ido mRNAs. The data demonstrate that circadian disruption can negatively impact affective state, and that this effect is pronounced in older individuals. Although clear associations between circadian arrhythmia and constitutive limbic proinflammatory activity were not evident, the present data suggest that social housing markedly inhibits constitutive hippocampal IL-1β and Ido activity, which may contribute to the ameliorating effects of social housing on a number of emotional behaviors.

Item Type:Articles
Additional Information:This work was supported by a seed grant from the Institute for Mind and Biology at the University of Chicago and NIH Grant AI-67406
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stevenson, Dr Tyler
Authors: Prendergast, B. J., Onishi, K. G., Patel, P. N., and Stevenson, T. J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Behavioural Brain Research
Publisher:Elsevier
ISSN:0166-4328
ISSN (Online):0166-4328
Published Online:12 December 2013

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