Subdiaphragmatic vagotomy does not block intraperitoneal lipopolysaccharide-induced fever.
Several recent findings, including the inability of subdiaphragmatic vagotomy to block lipopolysaccharide (LPS)-induced interleukin-1beta (IL-1beta) protein in brain, have made it necessary to reexamine the role of the subdiaphragmatic vagal afferents in immune-to-brain communication. In this study, we examined the effects of intraperitoneal (i.p.) injections of LPS on core body temperature in control and subdiaphragmatically vagotomized rats. Vagotomized and sham-operated male Sprague-Dawley rats were injected i.p. with vehicle (pyrogen-free saline) on the control day and LPS (1, 10 or 50 microg/kg) on the experimental day, and core body temperature was monitored by telemetry for 6 h after the injection. At this time, rats were sacrificed, and serum, liver, and pituitary samples were collected. The i.p. injection of LPS increased core body temperature in both sham-operated and vagotomized rats compared to the saline injection. In addition, LPS significantly increased IL-1beta levels in serum, liver, and pituitary compared to saline-injected controls. There were no significant differences in the magnitude of the fever or in the levels of IL-1beta in serum, liver, or pituitary between sham-operated and vagotomized rats. Thus, the current data indicate that, at the doses tested, subdiaphragmatic vagal afferents are not crucial for i.p. LPS-induced fever. Because several effects of vagotomy have been shown to be dependent on dose, we are currently investigating whether vagal afferents are involved in lower-dose i.p. LPS-induced fever.
Hansen
M K
MK
Department of Psychology, University of Colorado at Boulder, 80309, USA. mhansen@psych.colorado.edu
Daniels
S
S
Goehler
L E
LE
Gaykema
R P
RP
Maier
S F
SF
Watkins
L R
LR
D000818:Animals; D001921:Brain / Q000166:cytology / Q000276:immunology; D002766:Cholecystokinin / Q000494:pharmacology; D003964:Diaphragm; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D005334:Fever / Q000139:chemically induced / Q000276:immunology / Q000503:physiopathology*; D007274:Injections, Intraperitoneal; D007375:Interleukin-1 / Q000032:analysis / Q000097:blood; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000737:chemistry / Q000276:immunology; D008297:Male; D015213:Neuroimmunomodulation / Q000502:physiology*; D010902:Pituitary Gland / Q000737:chemistry / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014628:Vagotomy / Q000379:methods*; D014630:Vagus Nerve / Q000166:cytology / Q000276:immunology* / Q000601:surgery
D007375:Interleukin-1; D008070:Lipopolysaccharides; D002766:Cholecystokinin