BLOCKADE OF CYTOKINE-INDUCED CONDITIONED TASTE-AVERSION BY SUBDIAPHRAGMATIC VAGOTOMY - FURTHER EVIDENCE FOR VAGAL MEDIATION OF IMMUNE-BRAINCOMMUNICATION

Interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-al pha) are cytokines released by activated immune cells. IL-1 beta and T NF-alpha elicit various illness symptoms including avoidance of novel tastes with which they have been paired (conditioned taste aversion). Previous hypotheses to account for these actions have focused on blood -borne IL-1 beta and TNF-alpha exerting their effects directly at the brain. However, recent evidence suggests that these cytokines may acti vate subdiaphragmatic vagal afferents. The present experiments demonst rate that subdiaphragmatic vagal transection both attenuates acquisiti on and facilitates extinction of conditioned taste aversions induced b y i.p. administration of either IL-1 beta or TNF-alpha.