Individual differences in response to lps and psychological stress
in aged rats.
Wachulec, Maciek, Elizabeth Peloso, and Evelyn Satinoff.
Department of Psychology and Program in Neuroscience, University of
Delaware, Newark, DE 19716
APStracts 3:0412R, 1996.
Wachulec, Maciek, Elizabeth Peloso, and Evelyn Satinoff. Individual
differences in response to lps and psychological stress in aged rats.
Am. J. Physiol. (Regulatory Integrative Comp. Physiol.). Old rats may
show blunted fever or hypothermia after injection of
lipopolysaccharide (LPS), a fever-producing agent, and have a reduced
body temperature (Tb) rise in response to psychological stress. These
results may partly be a consequence of aging per se, partly a sex
difference, and partly an effect of differences in types and doses of
pyrogen. Here we tested age and gender differences in Tb responses to
30 min exposure to a novel environment and to injection of several
doses of LPS. There were age-related reductions in novelty-induced
hyperthermia and some old rats even became hypothermic. Sensitivity
to the pyrogenic activity of LPS decreased while sensitivity to the
toxic effects of endotoxin, manifested by hypothermia, increased in
aged rats. A major finding was that there were no correlations
between age-related changes in Tb in response to novelty and to LPS
injection. Tb responses in aged rats were variable; in each
situation, there were old rats whose Tb rose as high as did younger
ones. We did not observe significant gender differences in response
either to novelty or to LPS in young or old rats.
Received 12 August 1996; accepted in final form 5 November 1996.
APS Manuscript Number R476-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996