Effects of food deprivation on sleep and wakefulness in the rat

The effects of prolonged total food deprivation on paradoxical sleep (PS), slow-wave sleep (SWS), and wakefulness were studied in male albino rats. Analysis of sleep and waking patterns was based on daily 3-hr recordings of EEG, EOG, and EMG activity. The amount of wakefulness increased monotonically in a positively accelerating curve as a function of deprivation, while the amount of sleep declined reciprocally. After 6-11 days of food deprivation virtually all sleep had disappeared, with PS always disappearing before SWS. Animals that did not eat spontaneously when offered food ad libitum after the disappearance of sleep died within the next 24 hr. SWS declined gradually during the first few days of food deprivation and then rapidly declined toward zero. On the other hand, PS significantly increased in amount on the first day of deprivation and then stayed at approximately control level until 2 days before it disappeared completely. On the day after the return to ad libitum food, PS increased substantially above control level while SWS remained below control.