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Effects of muramyl dipeptide on sleep, body temperature and plasma copper after intracerebral ventricular
S Shoham1, R A Ahokas, C M Blatteis
1University of Tennessee, Department of Physiology and Biophysics, Memphis 38163.
Abstract:
Muramyl peptides are the monomeric components of bacterial cell wall peptidoglycans. Many muramyl peptides, such as muramyl dipeptide (MDP), (N-acetylmuramyl-L-alanyl-D-isoglutamine), are immune response modifiers, pyrogenic and somnogenic. The purposes of this study were to measure the somnogenic effects of MDP in conjunction with a biochemical measure of the host defense response, plasma Cu, and to determine if plasma Cu levels, like sleep, are regulated by a central nervous system process. MDP administered into a lateral cerebral ventricle induced a dose-dependent rise in plasma copper at 28 h postinfusion. This was usually associated with dose-dependent fevers, increases in SWS and reductions in rapid eye movement (REM) sleep during the first 6 h after infusion. Intravenous (i.v.) administration of the same amount of MDP did not affect any of these variables. We conclude that the syndrome induced by centrally administered MDP includes activation of the host defense response with respect to a rise in plasma copper in addition to fever and enhanced sleep.
Insights
Muramyl dipeptide (MDP), a bacterial component, promotes sleep and fever when administered centrally. It also increases plasma copper levels, indicating a host defense response regulated by the central nervous system.
Area of Science:
- Neuroscience
- Immunology
- Biochemistry
Background:
- Muramyl peptides are key components of bacterial cell walls.
- Muramyl dipeptide (MDP) is known to influence immune responses, fever, and sleep.
Purpose of the Study:
- To quantify the sleep-inducing effects of MDP.
- To assess plasma copper (Cu) levels as a host defense marker.
- To investigate central nervous system regulation of plasma Cu and sleep.
Main Methods:
- Administering MDP into the lateral cerebral ventricle of subjects.
- Measuring plasma copper levels at 28 hours post-infusion.
- Monitoring body temperature, slow-wave sleep (SWS), and rapid eye movement (REM) sleep.
Main Results:
- Central MDP administration caused a dose-dependent increase in plasma copper.
- This was accompanied by fever, increased SWS, and decreased REM sleep.
- Intravenous MDP administration did not produce these effects.
Conclusions:
- Centrally administered MDP activates host defense mechanisms, including elevated plasma copper.
- MDP's effects on sleep and fever suggest central nervous system regulation.
- Plasma copper serves as a biochemical indicator of the host defense response to MDP.