Are vagal efferents involved in the fever response to intraperitoneal lipopolysaccharide?

Subdiaphragmatic vagotomy decreases the febrile responsiveness to intraperitoneal (i.p.) lipopolysaccharide (LPS), but whether this effect is due to interruption of afferent or efferent vagal fibers remains unknown. To address this issue, we injected LPS (10 mu g/kg, i.p.) in four groups of rats: (i) subdiaphragmatically vagotomized at the trunk level; (ii) sham-vagotomized; (iii) selectively de-efferented (via combined right efferent rhizotomy and anterior gastroceliac branch vagotomy); and (iv) sham-de-efferented. The febrile response in both groups (i) and (iii) was attenuated two-fold as compared to groups (ii) and (iv), respectively. We suggest that motor vagal fibers may be involved in fever genesis, perhaps by interfering with LPS transport from the peritoneal cavity to the blood. (C) 2000 Elsevier Science Ltd. All rights reserved.