ABSTRACT
Muramyl peptides (MP) are known as components of peptidoglycans, which form the backbone of bacterial cell walls and exert profound pyrogenic and immunostimulatory activities in the mammalian body. Consequently, the possibility that MPs may be candidate substances for an endogenous sleep factor has led to the interesting hypotheses. Recently, J. M. Krueger and associates have extensively investigated the somnogenicity of bacterial peptidoglycans. They compared the somnogenic activity of 14 different compounds that were closely related to the active tri-and tetramuramyl peptides, and found that a disaccharide pentapeptide containing an additional alanine at the C-terminal. Another leukocyte product, tumor necrosis factor, also is a pyrogenic and immunoreactive substance. Shoham et al. examined the effects of recombinant human tumor necrosis factor on rabbit sleep and temperature. Narcolepsy is characterized by elevated daytime sleepiness and sleep paralysis. This sleep disorder is regarded as an autoimmune disease.
