Sleep and serotonin: an unfinished story

Neuropsychopharmacology. 1999 Aug;21(2 Suppl):24S-27S. doi: 10.1016/S0893-133X(99)00009-3.


Serotonin (5-HT) was first believed to be a true neuromodulator of sleep because the destruction of 5-HT neurons of the raphe system or the inhibition of 5-HT synthesis with p-chlorophenylalanine induced a severe insomnia which could be reversed by restoring 5-HT synthesis. However the demonstration that the electrical activity of 5-HT perikarya and the release of 5-HT are increased during waking and decreased during sleep was in direct contradiction to this hypothesis. More recent experiments suggest that the release of 5-HT during waking may initiate a cascade of genomic events in some hypnogenic neurons located in the preoptic area. Thus, when 5-HT is released during waking, it leads to an homeostatic regulation of slow-wave sleep.

Publication types

  • Review

MeSH terms

  • Animals
  • Fenclonine / pharmacology
  • Humans
  • Raphe Nuclei / physiology*
  • Serotonin / physiology*
  • Serotonin Antagonists / pharmacology
  • Sleep / physiology*
  • Sleep Initiation and Maintenance Disorders / chemically induced
  • Sleep Initiation and Maintenance Disorders / physiopathology


  • Serotonin Antagonists
  • Serotonin
  • Fenclonine