A comparison of febrile responses induced by LPS from E. coli and S. abortus in unrestrained rats placed in a thermal gradient
Bodurka, M.; Caputa, M.; Bodurka, J.
Journal of Physiology and Pharmacology An Official Journal of the Polish Physiological Society 48(1): 81-88
1997
ISSN/ISBN: 0867-5910 PMID: 9098828 Document Number: 479548
The purpose of our study was a comparison of pyrogenic and behavioural effects of Escherichia coli (E.coli) and Salmonella abortus (S.abortus) endotoxins in unrestrained, freely moving Wistar rats, placed in a thermal gradient and having an easy access to ambient temperatures within a range 5-40 degrees C. Hypothalamic and chosen by the rats ambient temperatures as well as locomotor activity were recorded before and after intraperitoneal injection of 1 mg/kg lipopolysaccharide from E. coli or from S. abortus. Control animals were injected with pyrogen-free saline. Both endotoxins induced warm-seeking behaviour which was accompanied by biphasic fever. Locomotor activity of LPS-injected rats was reduced. S. abortus-induced fever peaked at 100th minute (reaching 37.5 +/- 0.2 degrees C) and at 250th minute (reaching 38.1 +/- 0.1 degrees C). Respective data for E. coli fever were: 170th minute (when hypothalamic temperature reached 37.6 +/- 0.3 degrees C) and 430th minute (with hypothalamic temperature of 38.6 +/- 0.1 degrees C). Comparing to S. abortus-generated fever both peaks of E. coli LPS-induced fever were significantly delayed (p < 0.05). A limited structural variability of lipid A from both bacteria is likely to be responsible for the difference in fever timing recorded in this study.