Reversal of rapid eye movement sleep without atonia by chloramphenicol

Toxic effect of chloromycetin on the ultrastructures of the motor neurons of the Chinese tree shrew (Tupaia belangeri)

This paper describes the toxic effects of chloromycetin on the motor neurons of the Chinese tree shrew (Tupaia belangeri chinensis) with horse radish peroxidase (HRP) as the labeling enzyme. When chloromycetin was administered orally at 2.5 mg/kg (body weight)/day for 3 days, Chinese tree shrews showed evidence of neurotoxicity. This included damage in cortical motor neuron synapses ending on neurons of the red nucleus and the ultrastructural changes in the mitochondria such as swelling of these organelles and blurring of their cristae. There was an increase of the mitochondrial matrix density and of the thickness of the synaptic membranes. These observations indicate that chloromycetin can lead to ultrastructural change of terminals of the cortical motor axons, and that Chinese tree shrews are sensitive animal model for chloromycetin neurotoxicity.Key words: chloromycetin, red nuclei, motor neuron, ultrastructure, Chinese tree shrew, Tupaia belangeri.

Relationship between eye movements and oneiric behavior in cats

The relation between oneiric behavior and rapid eye movements (REMs) in paradoxical sleep (PS) without muscle atonia was analyzed in cats. Most isolated REMs were related to orienting behavior, whereas most REM bursts were related to generalized body movements (jumping, attacking, etc.). Only isolated, high amplitude REMs had any possibility of corresponding to visual images in dreams. From these findings we propose the existence of both dream-related and nondream-related REMs even in animals.

[Functions of paradoxical sleep and ontogenesis]

The hypotheses directly linked to cognitive and neurologic ontogenic processes ie consolidation of memory and learning, the maturation hypothesis of Roffwarg and the hypothesis of endogenous genetic programming of Jouvet, are analysed. The discussion of these theories are based on the analysis of: the neurophysiologic mechanism of REM sleep and its ontogenesis in human, the results of REM sleep deprivation in young animals and by a personal study of facial mimics during sleep in neonates. Active sleep could be assimilated, very early during ontogenesis, to REM sleep, it probably plays an important role in brain maturation during early development but the stimulation is probably, at this time, not very specific, later it could be a link between genetic programming and epigenetic processes.