Decreased Interleukin-4 Release from the Neurons of the Locus Coeruleus in Response to Immobilization Stress.
Mediators Inflamm 2016;
2016:3501905. [PMID:
26903707 PMCID:
PMC4745346 DOI:
10.1155/2016/3501905]
[Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 07/02/2015] [Accepted: 12/17/2015] [Indexed: 11/18/2022] Open
Abstract
It has been demonstrated that immobilization (IMO) stress affects neuroimmune systems followed by alterations of physiology and behavior. Interleukin-4 (IL-4), an anti-inflammatory cytokine, is known to regulate inflammation caused by immune challenge but the effect of IMO on modulation of IL-4 expression in the brain has not been assessed yet. Here, it was demonstrated that IL-4 was produced by noradrenergic neurons in the locus coeruleus (LC) of the brain and release of IL-4 was reduced in response to IMO. It was observed that IMO groups were more anxious than nontreated groups. Acute IMO (2 h/day, once) stimulated secretion of plasma corticosterone and tyrosine hydroxylase (TH) in the LC whereas these increments were diminished in exposure to chronic stress (2 h/day, 21 consecutive days). Glucocorticoid receptor (GR), TH, and IL-4-expressing cells were localized in identical neurons of the LC, indicating that hypothalamic-pituitary-adrenal- (HPA-) axis and sympathetic-adrenal-medullary- (SAM-) axis might be involved in IL-4 secretion in the stress response. Accordingly, it was concluded that stress-induced decline of IL-4 concentration from LC neurons may be related to anxiety-like behavior and an inverse relationship exists between IL-4 secretion and HPA/SAM-axes activation.
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