Glucocorticoid resistance following herpes simplex-1 infection: Role of hippocampal glucocorticoid receptors

Dafna Bener, Avital Wohlman, Anna Itzik, Raz Yirmiya, Tamir Ben-Hur, Joseph Weidenfeld*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Herpes simplex-1 (HSV-1) is a sporadic cause of viral encephalitis. We have previously demonstrated that corneal HSV inoculation markedly activates the hypothalamo-pituitary-adrenal (HPA) axis. This activation depends on host derived brain interleukine-1 and was resistant to pretreatment with dexamethasone (dex), possibly because immune factors such as pro-inflammatory cytokines can modify the binding capacity of glucocorticoids in the hippocampus. In the present study, we examined whether resistance of the HPA axis activation following intracerebral HSV-1 infection to dex-induced suppression is associated with modifications in hippocampal or pituitary glucocorticoids (GC) receptors or GC receptors in cultured astrocytes. Male rats were injected intracerebroventricularly with purified HSV-1 or vehicle. 48 h later, dex or vehicle was injected intraperitoneally. Rats were sacrificed 3.5 h later. ACTH and corticosterone (CS) were measured in the serum. Specific binding of 3H-dex was measured in the cytosolic fraction of the hippocampus and the pituitary. Dex failed to reduce ACTH and CS responses to HSV-1 infection. In contrast, dex significantly reduced ACTH and CS responses to acoustic neural stimuli. Infection with HSV-1 markedly reduced the hippocampal maximal specific binding of dex with no effect on the dissociation constant (Kd) values. HSV-1 had no effect on the binding of dex in the pituitary. Infection of cultured astrocytes with HSV-1 also reduced the maximal specific binding of dex, but increased the Kdvalue. The results suggest that HSV-1 induced GC resistance may be mediated by downregulation of GC receptors in hippocampal tissue. These results may clarify a mechanism responsible for GC resistance following immune challenges.

Original languageAmerican English
Pages (from-to)207-215
Number of pages9
JournalNeuroendocrinology
Volume85
Issue number4
DOIs
StatePublished - Jul 2007

Keywords

  • Glucocorticoid receptors
  • Glucocorticoids
  • Herpes simplex virus
  • Hippocampus
  • Negative feedback

Fingerprint

Dive into the research topics of 'Glucocorticoid resistance following herpes simplex-1 infection: Role of hippocampal glucocorticoid receptors'. Together they form a unique fingerprint.

Cite this