Suppression of paradoxical sleep (PS) following hypothalamic defence reactions in cats during normal conditions and recovery from PS deprivation

Abstract

Summary Intermittent electrical stimulation of a lateral hypothalamic defence area was applied in 7 chronically implanted cats for 0.5 h in 10 experiments in normal laboratory conditions and in 7 experiments following a 3 day PS deprivation. After the defence sequence the states of vigilance were quantitatively recorded for 15–24 h and compared with previously obtained controls from the same animals. A significant reduction of PS was obtained in normal conditions (37% below 15 h controls) and after PS deprivation (33% below 24 h controls). The changes in wake-fluness or slow-wave sleep were short lasting or insignificant. A well-established consequence of the type of stimulation used is a considerable drop in brain NE with little other effect on cerebral metabolites so far studied. The results are discussed in connection with the norepinephrinergic hypothesis of the control of emotional state and PS. The interpretation of the results is in favour of the notion that NE is involved in the tonic phenomena of PS.