DEPENDENCE OF SLEEP ON NUTRIENTS AVAILABILITY

Continuous EEG recordings were performed in lean (240-250 g) rats, in large size (300-380 g) rats and in Ventromedial Hypothalamic (VMH) lesioned obese (450-470 g) rats, during 4 days of food deprivation and 3 days following food restitution. Though the daily amounts of both Slow Wave Sleep (SWS) and Paradoxical Sleep (PS) were dramatically decreased in lean rats (particularly during the dark phase of the day) by the food deprivation, they remained unchanged in large size rats and also in VMH obese rats. In the latter, there was even a tendency to an increase of SWS during the first two days of starvation. Food restitution brought about a significant rebound in SWS and PS (largely based upon an increase during the dark phase of the diurnal cycle) in lean rats, but had no effect on the sleep parameters of large size and VMH obese rats. Replacement by glucose infusions (100% of the normal daily caloric intake) via a cardiac catheter of oral nutrients in food deprived rats also resulted in a similar increase of sleep duration. These findings suggest that sleep is dependent on the degree of availability of metabolizable substances at the cellular level. In addition, possible causative relations between sleep and feeding are discussed. © 1979.