Comparing two anti-inflammatory reflexes: Splanchnic and hypothalamic–pituitary–adrenal

Abstract

Both the autonomic nervous system and the hypothalamic–pituitary–adrenal axis respond to systemic immune challenge by initiating anti-inflammatory reflexes. Here we compare those two homeostatic responses in vivo. We first confirmed in male urethane-anaesthetized rats that disabling the autonomic reflex by bilateral section of the splanchnic sympathetic nerves increased plasma tumor necrosis factor α (TNF) responses to systemic lipopolysaccharide (LPS, 60 µg/kg i.v.) while reducing levels of the key anti-inflammatory cytokine, interleukin 10 (IL-10). Bilateral adrenalectomy, removing both adrenal catecholamines and glucocorticoids, increased TNF responses to LPS by a factor similar to splanc..