SLEEP-PROMOTING FUNCTIONS OF THE HYPOTHALAMIC MEDIAN PREOPTIC NUCLEUS: INHIBITION OF AROUSAL SYSTEMS

摘要

Current work on the hypothalamic preoptic area (POA) sleep-promoting mechanism has its roots in several landmark studies. First, more than 70 years ago, von Economo (45) reported that patients exhibiting insomnia in association with infectious encephalitis were found, post mortem, to have inflammatory lesions in the region of the POA. Later, Nauta (25) found that knife cuts bilaterally spanning the POA of rats were followed by sleeplessness, whereas posterior hypothalamic (PH) knife cuts were followed by somnolence. Rats with both POA and PH knife cuts were also somnolent. More recently, Sallanon et al. (32), from the laboratory of Prof. Jouvet, showed that acute inactivation of the PH could restore sleep in cats with insomnia produced by discrete POA lesions. Subsequent studies showed descending pathways from POA to posterior hypothalamus which could convey the sleep-promoting signals (15). These studies, and many other lesion studies (reviewed (22)), support a conclusion that the POA contains a sleep-promoting mechanism. Since the effects of PH lesions override effects of POA lesions they further suggested a hypothesis that the PH wake-promoting network was downstream from the POA sleep-promoting network and that the POA output inhibited the PH.