TNF-ALPHA-INDUCED CORTICOSTERONE ELEVATION BUT NOT SERUM-PROTEIN OR CORTICOSTEROID-BINDING GLOBULIN REDUCTION IS VAGALLY MEDIATED

Immune activation leads to production of mediators such as cytokines, which act to induce both brain-mediated and peripheral defense process es. We used intraperitoneal administration of the cytokine tumor necro sis factor-alpha (TNF-alpha) to investigate whether defense processes induced by this cytokine are mediated by vagal afferents and/or interl eukin-1 (IL-1) receptors. Because some effects of TNF-alpha are mediat ed, at least in part, by the brain [plasma corticosterone (CORT) eleva tion] and some are mediated by peripheral organs [reduction of serum p rotein and corticosteroid binding globulin (CBG)], we also investigate d whether the effects of vagotomy are specific to those defense proces ses mediated by the brain. Both vagotomy and IL-1 receptor antagonist attenuated serum CORT elevation, but had no effects on serum protein o r CBG reduction, These results support the idea that vagal afferents p rovide a true immune-to-brain pathway that may include IL-1 receptors. (C) 1997 Elsevier Science Inc.