The Effects of Melanin-Concentrating Hormone on Neurotransmitter Systems Involved in the Generation and Maintenance of Wakefulness
Within the central nervous system (CNS), melanin-concentrating hormone (MCH) participates in a number of functions including sleep-wake behavior. In this respect, MCHergic neurons project widely throughout the central nervous system (CNS) to neural structures involved in the regulation of wakefulness (W). An enhancement of REM sleep time has been described following the microinjection of MCH into the dorsal raphe nucleus (serotonergic neurons), locus coeruleus nucleus (noradrenergic neurons), and basal forebrain [(horizontal limb of the diagonal band of Broca) glutamatergic and cholinergic (W-on) neurons] of rodents. In addition, optogenetic stimulation of MCH terminals in the tuberomammillary nucleus (histaminergic neurons) is followed by an increase in the duration of REM sleep episodes. Moreover, the finding that the neuropeptide negatively modulates the mesolimbic dopaminergic function tends to indicate that the inhibition of nucleus accumbens and ventral tegmental nucleus dopaminergic neurons by MCH could facilitate the occurrence of REM sleep. Thus, the REM sleep-inducing and sleep-facilitating effect of MCH is at least partly related to the deactivation of monoaminergic, glutamatergic, and cholinergic (W-on) neurons.
KeywordsMelanin-concentrating hormone REM sleep Wakefulness Serotonin Norepinephrine Dopamine Glutamate Acetylcholine
- Lu J, Jhou TC, Saper CB (2006) Identification of wake-active dopaminergic neurons in the ventral periaqueductal gray matter. J Neurosci 26:191–202Google Scholar
- Pace-Schott EF, Hobson JA (2002) Basic mechanisms of sleep: new evidence on the neuroanatomy and neuromodulation of the NREM-REM cycle. In: Charney D, Nemeroff C (eds) Neuropsychopharmacology—the fifth generation of progress. Lippincott, Williams and Wilkins, Philadelphia, pp 1859–1877Google Scholar
- Semba K (2011) Preoptic and basal forebrain modulation of REM sleep. In: Mallick BN, Pandi-Perumal SR, McCarley R, Morrison AR (eds) REM sleep: regulation and function. Cambridge University Press, Cambridge, pp 99–109Google Scholar
- Skofitsch G, Jacobowitz DM, Zamir N (1985) Immunohistochemical localization of melanin-concentrating hormone-like peptide in the rat brain. Brain Res Bull 15:653–649Google Scholar