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Somnogenic, pyrogenic, and hematologic effects of bacterial peptidoglycan
L Johannsen1, L A Toth, R S Rosenthal
1Department of Physiology, University of Tennessee, Memphis 38163.
Abstract:
Bacterial infections and certain muramyl peptides elicit a variety of pathophysiological effects including increases in body temperature and slow-wave sleep. Bacterial cell wall peptidoglycan is composed of muramyl peptides. To investigate the ability of isolated bacterial cell walls to enhance slow-wave sleep, rabbits were injected intravenously with cell walls isolated from Staphylococcus aureus or with soluble peptidoglycan prepared from Neisseria gonorrhoeae. These injections increased slow-wave sleep, electroencephalographic delta-wave amplitudes, and body temperature, reduced rapid-eye-movement sleep, and induced neutrophilia and lymphopenia. The somnogenic and pyrogenic effects of S. aureus cell walls developed within 1 h and persisted throughout the recording period. Injections of N. gonorrhoeae peptidoglycan induced similar effects but of larger magnitude and shorter duration. We conclude that peptidoglycan is a bacterial component that mediates the increased sleep observed during infectious disease.
Insights
Bacterial peptidoglycans, components of bacterial cell walls, were found to increase slow-wave sleep and body temperature in rabbits. This research identifies peptidoglycans as key mediators of sleep changes during infections.
Area of Science:
- Microbiology
- Immunology
- Neuroscience
Background:
- Bacterial infections and muramyl peptides can cause fever and increased slow-wave sleep.
- Bacterial cell walls contain peptidoglycans, which are made of muramyl peptides.
Purpose of the Study:
- To investigate if isolated bacterial cell walls can enhance slow-wave sleep.
- To determine the role of bacterial peptidoglycans in sleep and fever during infection.
Main Methods:
- Rabbits were intravenously injected with cell walls from Staphylococcus aureus or soluble peptidoglycan from Neisseria gonorrhoeae.
- Physiological responses including sleep patterns, electroencephalographic delta-wave amplitudes, body temperature, and white blood cell counts were monitored.
Main Results:
- Injections of bacterial cell walls and peptidoglycans increased slow-wave sleep, delta-wave amplitudes, and body temperature.
- Rapid-eye-movement sleep was reduced, and neutrophilia and lymphopenia were observed.
- The effects of Staphylococcus aureus cell walls were observed within 1 hour and persisted, while Neisseria gonorrhoeae peptidoglycan effects were more potent but shorter in duration.
Conclusions:
- Peptidoglycan is a bacterial component responsible for the increased sleep observed during infectious diseases.
- Bacterial cell wall components play a significant role in the host's physiological response to infection, including sleep regulation and thermoregulation.