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Related to Orexins: suvorexant


Either of two neuropeptide hormones synthesized in the hypothalamus that regulate sleep and wakefulness and whose dysfunction causes narcolepsy. Also called hypocretin.

[Greek orexis, appetite (from the view that orexin stimulates appetite; see anorexia) + -in.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


a hormone that promotes wakefulness and stimulates the appetite
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
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Orexins are peptides that are synthesized in neurons or nuclei - orexinergic neurons send projections to the ventral tegmental area and nucleus accumbens.
Orexins are a new group of molecules released from neurons in certain parts of the brain.
On the other hand, adipose tissue acts as an endocrine organ by producing various signaling cytokines and interacting with some neuropeptides as orexins. Orexins are produced by the lateral hypothalamus and evidences have suggested that orexins promote energy expenditure (EE) through modulation of locomotor activity and BAT thermogenesis.
Consequently, it was found that central orexin/hypocretin activates hypothalamo-pituitary adrenal (HPA) axis and may be involved in stress-induced activation of the HPA axis by studying plasma levels of corticosteroids after intracerebroventricular (I.C.V) administration of both Orexins A and B.
Within the LHA, neurons expressing the wake-promoting peptides, orexins, are GI neurons, whereas neurons expressing the sleep-promoting neuropeptide melanin-concentrating hormone (MCH) are GE neurons [19, 20].
Orexins are produced in a particular area of the hypothalamus, including the caudal lateral hypothalamus and adjacent perifornical area [12] and, from these sites, orexin projects throughout the other areas of the brain.
As orexins are neuropeptides that are major regulators of the neural mechanisms underlying sleep and wakefulness, E2006 is being developed for the potential treatment of insomnia disorder.
Articles address socioeconomic correlations with obesity, neurological and endocrine effects of stress, calorie restriction, and sleep irregularity, and the complex interactions of neurotransmitters and hormones such as leptin and ghrelin, orexins, insulin, gluco- and mineralocorticoids, and brain-derived neurotrophic factor.
Although orexins are primarily expressed in the lateral hypothalamus, recent studies have demonstrated that both the orexins and their receptors are also expressed in the peripheral organs of the gastrointestinal and genital tracts.
Ishii et al., "Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior," Cell, vol.
Interaction between the corticotropin-releasing factor system and hypocretins (orexins): a novel circuit mediating stress response.
The drug, suvorexant, blocks the chemical messengers in the brain called orexins, which regulate wakefulness.