Orexin

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Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. A Corrigendum to this article was published on 20 October

Orexin

Federal government websites often end in. The site is secure. Preview improvements coming to the PMC website in October Learn More or Try it out now. The hypocretins orexins are recently described hypothalamic neuropeptides thought to have an important role in the regulation of sleep and arousal states 1. Their discovery was reported independently by two groups using different techniques. The terms orexin and hypocretin are synonymous and in this article we will use hypocretin Hcrt. The finding that cerebrospinal fluid CSF levels of these peptides were abnormal in patients with narcolepsy has stimulated research on the potential role of these peptides in human disease. We present here an overview of the pertinent findings from animal studies and a review of the published data from human studies, with a particular emphasis on narcolepsy. Finally, we consider the possible roles of these peptides in neurological and psychiatric disorders. In , a set of neuropeptides related to the hormone secretin were isolated from the rat lateral hypothalamus by the process of directional tag PCR subtraction cloning 4. The cloning of the gene for these peptides from rat and mouse, the localization of the peptide-producing cell bodies and a description of some of their efferent projections were first presented in 5 , 6. The receptors for these neuropeptides Hcrtr1 [Orxr1] and Hcrtr2 [Orxr2] have been identified as G-protein coupled receptors and shown in the rat brain, by analysis of their mRNA, to display a striking distribution 7 , 8.

It also orexin lipolysis and stimulates the secretion of adiponectin.

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. Humans and animals lacking orexin neurons exhibit daytime sleepiness, sleep attacks, and state instability.

Federal government websites often end in. The site is secure. Preview improvements coming to the PMC website in October Learn More or Try it out now. Orexins, also known as hypocretins, are two neuropeptides secreted from orexin-containing neurons, mainly in the lateral hypothalamus LH.

Orexin

The most common form of narcolepsy , type 1, in which the individual experiences brief losses of muscle tone "drop attacks" or cataplexy , is caused by a lack of orexin in the brain due to destruction of the cells that produce it. There are 50,—80, orexin-producing neurons in the human brain, [8] located predominantly in the perifornical area and lateral hypothalamus. Orexin was discovered in almost simultaneously by two independent groups of researchers working on the rat brain. Luis de Lecea, Thomas Kilduff , and colleagues reported the discovery of the hypocretin system at the same time as Takeshi Sakurai from Masashi Yanagisawa 's lab at the University of Texas Southwestern Medical Center at Dallas reported the discovery of the orexins to reflect the orexigenic appetite-stimulating activity of these peptides.

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Download PDF. No use, distribution or reproduction is permitted which does not comply with these terms. Kastin, A. These authors jointly supervised this work: Patrick M. Matzeu, A. Orexinergic system dysregulation, sleep impairment, and cognitive decline in Alzheimer disease. CiteSeerX Kroeger, D. Neuropeptide Y injected in the paraventricular hypothalamus: a powerful stimulant of feeding behavior. Narcolepsy in orexin knockout mice: molecular genetics of sleep regulation. Clinical and biochemical effects of catecholamine depletion on antidepressant-induced remission of depression.

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Reduced number of hypocretin neurons in human narcolepsy. Neurology 79, — The hypocretins: hypothalamus-specific peptides with neuroexcitatory activity. Figure 2. These results indicate that orexin neurons are tonically activated by glutamate. Neuronal dynamics direct cerebrospinal fluid perfusion and brain clearance Article 28 February A selective orexin-1 receptor antagonist reduces food consumption in male and female rats. Laprairie Psychopharmacology Noradrenergic tone is not required for neuronal activity-induced rebound sleep in zebrafish Eleanor Benoit Declan G. Atasoy, D. Studies indicate that a major role of the orexin system is to integrate metabolic, circadian and sleep debt influences to determine whether an animal should be asleep, or awake and active.