title: A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep.
abstract: BACKGROUND
  Peptidergic neurons containing the melanin-concentrating hormone (MCH) and the hypocretins (or orexins) are intermingled in the zona incerta, perifornical nucleus and lateral hypothalamic area. Both types of neurons have been implicated in the integrated regulation of energy homeostasis and body weight. Hypocretin neurons have also been involved in sleep-wake regulation and narcolepsy. We therefore sought to determine whether hypocretin and MCH neurons express Fos in association with enhanced paradoxical sleep (PS or REM sleep) during the rebound following PS deprivation. Next, we compared the effect of MCH and NaCl intracerebroventricular (ICV) administrations on sleep stage quantities to further determine whether MCH neurons play an active role in PS regulation.
  
  
  RESULTS
  Here we show that the MCH but not the hypocretin neurons are strongly active during PS, evidenced through combined hypocretin, MCH, and Fos immunostainings in three groups of rats (PS Control, PS Deprived and PS Recovery rats). Further, we show that ICV administration of MCH induces a dose-dependent increase in PS (up to 200%) and slow wave sleep (up to 70%) quantities.
  
  
  CONCLUSIONS
  These results indicate that MCH is a powerful hypnogenic factor. MCH neurons might play a key role in the state of PS via their widespread projections in the central nervous system.
authors.affiliation: CNRS UMR5167, Institut Fédératif des Neurosciences de Lyon (IFR 19), Université Claude Bernard Lyon I, 7 Rue Guillaume Paradin, 69372 LYON Cedex 08, FRANCE. verret@sommeil.univ-lyon1.fr
authors.forename: Laure
authors.initials: L
authors.lastname: Verret
authors.forename: Romain
authors.initials: R
authors.lastname: Goutagny
authors.forename: Patrice
authors.initials: P
authors.lastname: Fort
authors.forename: Laurène
authors.initials: L
authors.lastname: Cagnon
authors.forename: Denise
authors.initials: D
authors.lastname: Salvert
authors.forename: Lucienne
authors.initials: L
authors.lastname: Léger
authors.forename: Romuald
authors.initials: R
authors.lastname: Boissard
authors.forename: Paul
authors.initials: P
authors.lastname: Salin
authors.forename: Christelle
authors.initials: C
authors.lastname: Peyron
authors.forename: Pierre-Hervé
authors.initials: PH
authors.lastname: Luppi
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis; D002452:Cell Count; D002490:Central Nervous System / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D004576:Electromyography; D007028:Hypothalamic Hormones / Q000096:biosynthesis* / Q000494:pharmacology; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008543:Melanins / Q000096:biosynthesis* / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009479:Neuropeptides / Q000096:biosynthesis; D000068797:Orexins; D010907:Pituitary Hormones / Q000096:biosynthesis* / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D012894:Sleep Stages / Q000187:drug effects / Q000502:physiology; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D007028:Hypothalamic Hormones; D047908:Intracellular Signaling Peptides and Proteins; D008543:Melanins; D009479:Neuropeptides; D000068797:Orexins; D010907:Pituitary Hormones; D016760:Proto-Oncogene Proteins c-fos; C019463:melanin-concentrating hormone