In the present study, we examined whether the vagus nerve is involved in mediating lipopolysaccharide (LPS)-induced appearance of IL-1beta immunoreactive cells in the brain and pituitary gland. Rats were either sham-operated or subjected to subdiaphragmatic vagotomy. Four weeks later, pyrogen free saline or 400 microg/kg LPS was administered to the rats intraperitoneally. Four and 8 h later, the animals were intracardially perfused with 4% paraformaldehyde and tissues were prepared for IL-1beta immunocytochemistry. IL-1beta positive cells were observed at both time-intervals after LPS administration in the choroid plexus, meninges, circumventricular organs and pituitary gland of both sham-operated and vagotomized rats. We conclude that under the conditions studied, the vagus nerve does not mediate LPS-induced appearance of IL-1beta in the rat brain and pituitary gland.