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The effect of some bacterial products on temperature and sleep in rat
Abstract:
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.
Insights
Bacterial products like lipopolysaccharides and mucopeptides can alter body temperature and disrupt sleep patterns in rats. These effects are linked to changes in serotonin (5-HT) turnover in the brain, suggesting a role for 5-HT neurons in fever induction.
Area of Science:
- Neuroscience
- Immunology
- Microbiology
Background:
- Bacterial components, such as lipopolysaccharides (LPS) and mucopeptides, are known pyrogens.
- Fever and sleep disturbances are common physiological responses to bacterial infections.
Purpose of the Study:
- To investigate the effects of bacterial products on body temperature and sleep in rats.
- To explore the role of neurotransmitters, specifically 5-hydroxytryptamine (5-HT) and noradrenaline (NA), in mediating these responses.
- To determine the involvement of the raphe nuclei in bacterial-induced fever.
Main Methods:
- Intravenous injection of lipopolysaccharides from P. aeruginosa and S. minnesota, and mucopeptide from Streptococcus group A into rats.
- Monitoring of body temperature and sleep patterns, including paradoxical sleep.
- Measurement of 5-HT and NA turnover rates in the hypothalamus and midbrain.
- Electrolytic lesions of the dorsal raphe nuclei.
Main Results:
- Bacterial products induced dose-dependent fever and significant sleep disturbances, particularly a decrease in paradoxical sleep.
- Salicylate reduced fever but did not affect sleep disturbance.
- Streptococcal mucopeptide increased 5-HT turnover in the hypothalamus and midbrain during fever and paradoxical sleep deprivation.
- Lesions in the dorsal raphe nuclei abolished the pyrogenic effect of mucopeptide.
Conclusions:
- Bacterial products can induce fever and alter sleep by affecting 5-HT pathways.
- The 5-HT-containing neurons in the dorsal raphe nuclei play a crucial role in mediating bacterial-induced fever.
- These findings suggest a mechanism by which bacterial components may trigger fever through interactions with the central nervous system.