The effect of some bacterial products on temperature and sleep in rat.

The lipopolysaccharides from P. aeruginosa, S. minnesota and mucopeptide from Streptococcus group A injected intravenously into rats induce a dose-dependent changes of temperature. Simultaneously, a profound disturbance of sleep occurs. The administration of salicylate, which markedly suppressed the fever does not influence the mucopeptide-caused sleep disturbance. The most prominent change in the sleep pattern is a marked decrease of the total time of paradoxical sleep. The measurement of turnover rates of 5-hydroxytryptamine (5-HT) and noradrenaline (NA) in hypothalamus and midbrain, areas involved in temperature and sleep control, after injection of streptococcal mucopeptide demonstrated a significant increase of 5-HT turnover in both areas during fever and paradoxical sleep deprivation. Small electrolytic lesions of the dorsal raphe nuclei which are the largest collection of neural cells containing 5-HT completely eliminated the pyrogenic potency of mucopeptide. The findings suggest that some bacterial products might increase the body temperature through the interference with activity of 5-HT-containing neurons of the raphe complex.