Interleukin-6 and tumor necrosis factor-alpha production after acute psychological stress, exercise, and infused isoproterenol: Differential effects and pathways

Objective: The aim of the study was to assess the effects of three differen t methods of acute activation of the sympathetic nervous system on lipopoly saccharide-induced in vitro production of interleukin-6 (IL-6) and tumor ne crosis factor-alpha (TNF-alpha). Methods: Thirty-two healthy volunteers per formed speech and exercise tasks and underwent a 30-minute infusion of isop roterenol. Results: As expected, acute activation of the sympathetic nervou s system led to leukocytosis, including increases in lymphocyte, monocyte, and granulocyte populations (p values < .05). Lipopolysaccharide-induced IL -6 production was increased after both the speaking and exercise tasks (p v alues < .001), whereas TNF-alpha production was elevated only after exercis e (p < .05). In contrast, infusion of isoproterenol inhibited TNF-alpha pro duction (p < .001) and caused no change in IL-6 production. Conclusions: In response to the challenges, IL-6 and TNF-alpha production showed different profiles. Purely beta-agonist stimulation led to downregulation of TNF-alp ha production, providing evidence of the antiinflammatory effect of in vivo beta-receptor activation. The enhanced production of both cytokines after exercise, and of IL-6 after the speech task, can be best explained by a sim ultaneous upregulation of proinflammatory and inflammation-responding media tors. These effects may have an important role in controlling the immune re sponse to acute psychological and physical stress.