Effects on sleep of melanin-concentrating hormone (MCH) microinjections into the dorsal raphe nucleus

MCH levels in the CSF, brain preproMCH and MCHR1 gene expression during paradoxical sleep deprivation, sleep rebound and chronic sleep restriction

“…Furthermore, the activation of MCHergic neurons by means of the optogenetic technique promotes sleep, mainly PS [9,11,32]. The role of MCH in the modulation of sleep in different brain areas, such as the dorsal raphe nucleus, the preoptic area and the basal forebrain of the rat, as well as in the nucleus pontis oralis of the cat was characterized [4,12,13,29]. Microinjection of MCH into these nuclei resulted in an increase of PS and/or SWS.…”

Microinjection of the melanin-concentrating hormone into the lateral basal forebrain increases REM sleep and reduces wakefulness in the rat

“…In this respect, MCH neurons fire selectively during sleep, predominantly during REMS (Hassani et al, 2009), and the intracerebroventricular administration of MCH increases REMS and SWS in the rat (Verret et al, 2003). Moreover, an enhancement of REMS has been described following the microinjection of the neuropeptide into the nucleus pontis oralis of the cat , whereas its infusion into the DRN induced an increase of REMS and SWS and a reduction of W in the rat (Lagos et al, 2009). On the other hand, immunoneutralization of MCH in the DRN provoked the opposite effects .…”

“…The doses of MCH selected for the present study were based on prior work in our laboratory (Lagos et al, 2009). MCH (50 and 100 ng in 0.2 μl of sterile saline, Phoenix Pharmaceutical Inc., Belmont, CA) or vehicle (0.2 μl of sterile saline) was microinjected into the right and left HDB.…”

Treatment of cataplexy

“…Whereas the MCH neurons are silent during wakefulness and are most active during REM sleep, hypocretin neurons are most active during wakefulness and virtually silent during REM sleep [81]. Additionally, ICV injection of MCH significantly increases time spent in REM sleep [82], and mice lacking the MCH peptide [83] or receptor [84] display altered sleep patterns. These data strongly demonstrates that the MCHergic system promotes sleep, but especially REM sleep.…”