Verret Laure, Goutagny Romain, Fort Patrice, Cagnon Laurène, Salvert Denise, Léger Lucienne, Boissard Romuald, Salin Paul, Peyron Christelle, Luppi Pierre-Hervé
CNRS UMR5167, Institut Fédératif des Neurosciences de Lyon (IFR 19), Université Claude Bernard Lyon I, 7 Rue Guillaume Paradin, 69372 LYON Cedex 08, FRANCE.
BMC Neurosci. 2003 Sep 9;4:19. doi: 10.1186/1471-2202-4-19.
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.
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.
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.
含有黑色素浓缩激素（MCH）和下丘脑泌素（或食欲素）的肽能神经元相互交织于未定带、穹窿周核和下丘脑外侧区。这两类神经元均参与能量稳态和体重的综合调节。下丘脑泌素神经元还与睡眠-觉醒调节及发作性睡病有关。因此，我们试图确定在快速眼动睡眠（PS或REM睡眠）剥夺后的反弹期间，下丘脑泌素和MCH神经元是否会伴随增强的PS而表达Fos。接下来，我们比较了脑室内（ICV）注射MCH和氯化钠对睡眠阶段量的影响，以进一步确定MCH神经元在PS调节中是否发挥积极作用。
在此我们表明，通过对三组大鼠（PS对照组、PS剥夺组和PS恢复组大鼠）进行下丘脑泌素、MCH和Fos联合免疫染色证明，在PS期间MCH神经元而非下丘脑泌素神经元强烈激活。此外，我们表明脑室内注射MCH会导致PS量（增加高达200%）和慢波睡眠量（增加高达70%）呈剂量依赖性增加。
这些结果表明MCH是一种强大的促眠因子。MCH神经元可能通过其在中枢神经系统中的广泛投射在PS状态中发挥关键作用。
