In the rat sub diaphragmatic vagotomy has prevented the effects of intraperitoneal IL-1 administration which prevented increases in body temperature and the increase in secreted hypothalamic norepinephrine (NE), and markedly attenuated the increases in plasma ACTH and corticosterone 8. This is thought to have reduced the "sickness response" to intraperitoneal cytokine administration. Similarly, administration of localised partial body exposure to irradiation in vagotomised rats resulted in decreased hypothalamic, thalamic, hippocampal and cortical IL-6, IL-1b and TNF-a compared with non-vagotomised rats 9. It is therefore thought that the vagus plays a major role in the surgical stress response although it is important to point that the vagus is not thought to be solely responsible for the activation of hypothalamic activity 10.