Effect of cervical vagotomy on sympathetic nerve responses to peripheral interleukin-1 beta

Although the vagus nerve is an important neural pathway mediating immune-to -brain communication, the role of the vagus in mediating sympathetic nerve discharge (SND) responses to peripheral cytokines is not well established. In the present study we determined renal, interscapular brown adipose tissu e (IBAT), splenic, and lumbar SND responses before and for 60 min after the intravenous administration of interleukin-1 beta (IL-1 beta, 100 ng) in ch loralose-anesthetized, sham-vagotomized and cervical-vagotomized (bilateral ) rats. In sham-vagotomized rats, IL-1 beta administration increased (P<0.0 5) splenic and lumbar SND while renal and IBAT SND remained unchanged from control levels. Renal, splenic, and lumbar SND were increased (P<0.05) wher eas IBAT SND remained unchanged from control after IL-1 beta in vagotomized rats. Renal, splenic, and lumbar SND responses were significantly higher a fter IL-1 beta in vagotomized compared with sham-vagotomized rats. These re sults demonstrate that regionally-selective SND (renal, splenic, and lumbar ) responses to IL-1 beta can occur in the absence of the vagus nerve and su ggest that the vagus nerve provides a tonic inhibition to the discharges in these nerves in response to peripheral IL-1 beta. (C) 2001 Elsevier Scienc e B.V. All rights reserved.