title: Sex differences in sleep: the response to sleep deprivation and restraint stress in mice.
abstract: OBJECTIVE
  Numerous clinical studies and sleep surveys have shown pronounced sex differences in the occurrence of insomnia and other sleep pathologies. It has been suggested that sex differences in sleep, while subtle under baseline conditions, may increase in magnitude under biological or environmental challenges. However, controlled and experimental studies on sleep under challenged conditions rarely include female subjects. In this context, we examined sex differences in sleep in the mouse, not only under baseline conditions, but also after sleep deprivation and restraint stress.
  
  
  METHODS
  Adult male and female C57BL/6J mice were implanted with electrodes to record sleep-wake architecture and sleep electroencephalogram under baseline conditions and after 6 hours of sleep deprivation or 1 hour of restraint stress at the beginning of the daily light phase.
  
  
  RESULTS
  Although baseline sleep patterns slightly differed between the sexes, the homeostatic recovery response to sleep deprivation was similar. In contrast, the changes in sleep after restraint stress were markedly different between male and female mice, with males displaying a stronger initial suppression of sleep and a stronger rebound of rapid-eye-movement sleep later in the recovery phase.
  
  
  CONCLUSIONS
  In mice, the fundamental homeostatic properties of sleep regulation may not differ between the sexes, but the way sleep is affected and disrupted by environmental influences may be sex dependent. The latter may reflect sex differences in stress sensitivity.
authors.affiliation: Institute F Magendie, INSERM U588, University of Bordeaux 2, Bordeaux, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Koehl
authors.forename: Sally
authors.initials: S
authors.lastname: Battle
authors.forename: Peter
authors.initials: P
authors.lastname: Meerlo
mesh_terms: D000818:Animals; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004576:Electromyography; D030762:Estrous Cycle; D005260:Female; D006706:Homeostasis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012149:Restraint, Physical / Q000523:psychology*; D012737:Sex Factors; D012892:Sleep Deprivation / Q000453:epidemiology / Q000503:physiopathology*; D020178:Sleep Disorders, Circadian Rhythm / Q000453:epidemiology / Q000503:physiopathology; D012895:Sleep, REM / Q000502:physiology; D013315:Stress, Psychological / Q000209:etiology*