Rapid eye movement (rem) sleep deprivation: effect on acid mucopolysaccharides in rat brain

The effect of rapid eye movement (REM) sleep deprivation on the total content and proportion of different mucopolysaccharides (AMPS) containing uronic acid in rat brain was studied. REM sleep deprivation was induced by the water tank methods. Five experimental groups of animals were used: control, stressed, REM sleep deprived, post-stress sleeping and post-deprivation sleeping rats. No changes of AMPS were observed in any of the experimental groups when the whole brain was analysed. A significant increase of AMPS was found in the cerebral hemispheres of stressed and REM deprived rats. A significant decrease of AMPS was observed in the cerebellum and brain stem. A further increase of AMPS was found in the cerebral hemispheres after the rebound of REM sleep following its deprivation, and after the recovery sleep following the stress. A significant increase of AMPS was found in the brain stem of rats allowed to recuperate after REM deprivation or stress as compared with the stressed and REM deprived animals. Recovery sleep induced a significant increase of AMPS in the cerebellum in previously stressed rats, while previously REM deprived rats exhibited a further decrease of AMPS from control values. The possible functional meaning of these results is discussed in relation to the role of REM sleep in protein synthesis and learning and memory processes. Intriguing, well-controlled positive findings and the fact that no experimental design is known where stress is minimal while REM deprivation is 100 per cent, justify and encourage continued efforts in studying the biochemical state of the brain during sleep and/or its alterations.