Fever suppression by subdiaphragmatic vagotomy in guinea pigs
depends on the route of pyrogen administration.
Goldbach, J[diaeresis]org-Michael, Joachim Roth, and Eugen Zeisberger.
Physiologisches Institut, Klinikum der Justus-Liebig
-Universit[umlaut]at, 35392 Giessen, Germany
APStracts 3:0343R, 1996.
It has recently been shown that subdiaphragmatic vagotomy blocks some
of the effects of inflammatory stimuli on brain-controlled functions.
Therefore, vagal afferent fibers have been proposed to play a
prominent role in the communication pathways between the immune
system and the brain. In the present study we investigated the effect
of subdiaphragmatic vagotomy on fever induced by intraperitoneal
(i.p.) or intramuscular (i.m.) injection of lipopolysaccharide (LPS)
or muramyl-dipeptide (MDP), which are both cytokine-inducing agents
in guinea pigs. I.p. and i.m. injections of LPS or MDP were tested in
the same animal with an interval of one week. In one experiment i.p.
injections of LPS or MDP were performed at the beginning followed by
i.m. injections one week later. In another experiment i.m injections
of LPS or MDP were performed at the beginning followed by i.p.
injections one week later. The febrile response to i.p. injection of
LPS was almost completely abrogated in vagotomized animals compared
to sham-operated controls ( from 30-330 min post i.p. injection of
LPS). The suppression of LPS-fever was quantitatively the same in
both experiments. In contrast, the response to i.m. injection of LPS
was the same in vagotomized and sham-operated guinea pigs in each of
the experiments. Fever induced by i.p. injection of MDP was partly
attenuated by subdiaphragmatic vagotomy (between 150 and 300 min post
i.p. injection of MDP) in both experiments. Again, the febrile
response to i.m. injections of MDP was not significantly altered by
subdiaphrag-matic vagotomy. In conclusion, the suppressive effect of
subdiaphragmatic vagotomy on fever induced by peripheral immune
-stimuli depends on the route of pyrogen administration. Since the
febrile response to i.p. injection of bacterial pyrogens is strongly
diminished in vagotomized guinea pigs it is suggested that vagal
afferent fibers play a crucial role in the transduction of immune
signals from the abdominal cavity to the brain.
Received 30 January 1996; accepted in final form 26 August 1996.
APS Manuscript Number R5-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996