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Neural reflex control of immunity: the splanchnic anti‐inflammatory pathway (875.1)
Author(s) -
Martelli Davide,
Yao Song,
McKinley Michael,
McAllen Robin
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.875.1
Subject(s) - splanchnic nerves , splanchnic , efferent , medicine , vagus nerve , reflex , vagotomy , sympathetic nervous system , autonomic nervous system , endocrinology , lipopolysaccharide , hemodynamics , stimulation , blood pressure , heart rate , afferent
Exaggerated or insufficient inflammatory responses can both be life threatening, and the nervous system helps maintain inflammation within appropriate limits. It is believed that the parasympathetic vagus nerve acts via the splenic sympathetic nerve to down‐regulate the cytokine response to immune challenge. Here we report that the systemic inflammatory response in rats, measured by plasma levels of tumour necrosis factor‐α 90 minutes after intravenous lipopolysaccharide (LPS, 60μg/kg), was unaffected by vagotomy but was enhanced five‐fold if the splanchnic sympathetic nerves were cut. Plasma corticosterone levels were unaffected, so did not contribute. Electrophysiological recordings demonstrated that efferent neural activity in the splanchnic nerve and its splenic branch was increased at least four‐fold after LPS. Furthermore, we show that, under these conditions, the increase in the efferent neural activity in the splenic sympathetic nerves is entirely driven by the splanchnic nerves, not the vagi. Thus, immune challenge triggers a powerful inhibitory reflex that suppresses the inflammatory response. Its efferent pathway is in the splanchnic sympathetic nerves, not the vagi as previously thought. Grant Funding Source : Supported by NHMRC project grant 1051102