Volume 16 Supplement 3
Noradrenergic neurons regulate the egress and trafficking of splenic monocytes and influence mortality during Gram-negative infection in mice
© Seeley et al.; licensee BioMed Central Ltd. 2012
Published: 14 November 2012
Neurotransmitters derived from the autonomic nervous system can regulate inflammatory cytokine secretion. This has been extensively studied in the parasympathetic nervous system, where acetylcholine regulates the secretion of TNF from splenic macrophages during LPS-induced inflammation. However, the role of noradrenergic neurons during mouse models of infection has not been characterized. The goal of these experiments was to study the influence of noradrenergic neurons on the immune response during Gram-negative septic peritonitis in mice.
Peripheral noradrenergic nerves were ablated using 6-hydroxydopamine (6-OHDA), a commonly employed method for studying noradrenergic neurons. Four days later, septic peritonitis was induced by i.p. injection of 150 CFU Klebsiella pneumoniae. Survival, serum and peritoneal bacterial loads, inflammatory cytokine production and leukocyte recruitment were studied at multiple time points after infection. To assess the importance of the NE containing splenic nerve, survival experiments on splenectomized mice with or without 6-OHDA treatment were performed.
These results suggest that splenic nerve-derived catecholamines regulate the egress of splenic monocytes during infection and that altering this pathway can alter survival during septic peritonitis in mice. These data highlight the emerging role of splenic monocytes during inflammation and infection  and add to the body of evidence that the immunosuppressive effects of catecholamines can impair innate immune responses during infection . These experiments may have important implications for patients receiving vasopressors in the ICU.
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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.