Animals were anesthetized i.m. with 100 mg/kg ketamine and 10 mg/kg xylazine, and subjected to sham surgery (sham) or left cervical vagotomy with electrical stimulation of the distal nerve trunk. In sham-operated animals, the vagal trunk was exposed but not divided. The nerve trunk was placed across a bipolar platinum electrode (Plastics One) connected to a stimulation module (STM100A) controlled by AcqKnowledge software (Biopac Systems). Stimulation (1 V, 2 ms, 5 Hz) was applied for 10 min before and after endotoxin administration.