First and second phases of biphasic fever: two sequential stages of the sickness syndrome?

• DOI: 10.1152/ajpregu.1996.271.1.r244
• Publication Date: 2017-12-25T04:12:33Z
• Authors: A. A. Romanovsky; V. A. Kulchitsky; N. V. Akulich; S. V. Koulchitsky; C. T. Simons; D. I. Sessler; V. N. Gourine
• Keywords: Lipopolysaccharides; Male; Dose-Response Relationship, Drug; Fever; Nociceptors; Pain; Syndrome; Motor Activity; Body Temperature; Rats; 3. Good health; 03 medical and health sciences; 0302 clinical medicine; Animals; Rats, Wistar; Skin Temperature

We hypothesized that the systemic inflammatory response undergoes two consecutive stages, each characterized by different nonspecific sickness patterns. To test this hypothesis, we studied thermal, nociceptive, and motor responses to lipopolysaccharide (LPS) in 43 unanesthetized, habituated, lightly restrained male Wistar rats previously implanted with a catheter jugular vein. Escherichia coli LPS was injected intravenously dose of 0, 0.1, 1, 10, 100, or 1,000 micrograms/kg. Colonic temperature (Tc) measured thermocouple. Changes nociception were assessed tail flick latency (TFL) noxious heat stimulus. Motor activity evaluated using an observation-based score (AS). The lowest doses apyrogenic. next induced monophasic fever maximal Tc rise 0.9 +/- 0.2 degrees C at 108 11 min post-LPS. higher caused biphasic fevers first second peaks 0.7 0.1 1.4 (10 micrograms/kg) (100 occurring 60 6 165 17 45 3 141 min, respectively. highest resulted fall (nadir, -0.6 degree 83 min). Two patterns exhibited. (high Tc, low TFL high AS) occurred during (early) phase fevers, it termed early syndrome. pattern TFL, developed (late) LPS-hypothermia (endotoxin shock), late Occurring stages developing through coping [fight/flight (energy expenditure) vs. depression/withdrawal conservation)], syndromes represent types adaptation infection have biological significance. Viewing as dynamic entity is justified clinically. Such approach problem resolves several contradictions current concept sickness.