Endogenous glucocorticoids protect against TNF-alpha-induced increases in anxiety-like behavior in virally infected mice

M. N. Silverman, M. G. Macdougall, F. Hu, T. W.W. Pace, C. L. Raison, A. H. Miller

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Endogenous glucocorticoids restrain proinflammatory cytokine responses to immune challenges such as viral infection. In addition, proinflammatory cytokines induce behavioral alterations including changes in locomotor/exploratory activity. Accordingly, we examined proinflammatory cytokines and open-field behavior in virally infected mice rendered glucocorticoid deficient by adrenalectomy (ADX). Mice were infected with murine cytomegalovirus (MCMV), and open-field behavior (36 h post-infection) and plasma concentrations of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 (42 h post-infection) were assessed. Compared to sham-ADX-MCMV-infected animals, ADX-MCMV-infected mice exhibited significant reductions in total distance moved, number of center entries, and time spent in center. These behavioral alterations were accompanied by significantly higher plasma concentrations of TNF-alpha and IL-6, both of which were correlated with degree of behavioral change. To examine the role of TNF-alpha in these behavioral alterations, open-field behavior was compared in wild-type (WT) and TNF-R1-knockout (KO), ADX-MCMV-infected mice. TNF-R1-KO mice exhibited significantly attenuated decreases in number of rearings, number of center entries and time spent in center, but not distance moved, which correlated with plasma IL-6. Given the potential role of brain cytokines in these findings, mRNA expression of TNF-alpha, IL-1 and IL-6 was assessed in various brain regions. Although MCMV induced increases in proinflammatory cytokine mRNA throughout the brain (especially in ADX animals), no remarkable differences were found between WT and TNF-R1-KO mice. These results demonstrate that endogenous glucocorticoids restrain proinflammatory cytokine responses to viral infection and their impact on locomotor/exploratory activity. Moreover, TNF-alpha appears to mediate cytokine-induced changes in open-field behaviors, especially those believed to reflect anxiety.

Original languageEnglish (US)
Pages (from-to)408-417
Number of pages10
JournalMolecular Psychiatry
Volume12
Issue number4
DOIs
StatePublished - Apr 30 2007
Externally publishedYes

Keywords

  • Anxiety
  • Glucocorticoids
  • Open-field behavior
  • TNF-R1-knockout mice
  • TNF-alpha
  • Viral infection

ASJC Scopus subject areas

  • Molecular Biology
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience

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