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orexin (ORX),

Neuropeptide involved in neuroendocrine function including feeding and drinking behavior; two subtypes, A and B, exist.
Farlex Partner Medical Dictionary © Farlex 2012


Either of two neuropeptide hormones synthesized in the hypothalamus that regulate sleep and wakefulness and whose dysfunction causes narcolepsy. Also called hypocretin.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


A class of hypothalamic neuropeptide hormones that regulates sleep cycles and energy expenditure; they probably do not directly affect appetite, as was once believed.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


One of a pair of centrally-acting neuropeptides produced by the lateral hypothalamus where the sensation of hunger is mediated. Rats given orexin will eat about ten times the normal amount of food and rats starved for 48 hours have more than twice the normal concentrations of orexin. There are also specific receptors for the two orexins. These facts are being exploited in the design of drugs that can both stimulate and reduce appetite.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
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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.
mRNA for the precursor of orexin, preproorexin, is abundantly and specifically produced in the LH and adjacent areas.
Dec 10, 2014: Eisai Demonstrates Efficacy of Investigational Dual Orexin Receptor Antagonist E2006 in Sleep Initiation and Maintenance 88
KEY WORDS: Adipose Tissue; Orexin; Autonomic Nervous System; Thermogenesis; Eating Behavior
Neuroanatomical studies have also suggested how the two neuropeptides in question can have a possible link in the pathogenesis of any possible stress system (two very opposite stress provocation have been cited previously), it is important to put anatomical evidence of nociceptin and orexin regulation or vice versa.
In addition, this recommendation is classified as "weak," and the associated evidence "low-quality." Medications reviewed included eszopiclone, zaleplon, Zolpidem, orexin receptor antagonist, melatonin, ramelteon, and benzodiazepines.
Table 1 11 Pharmacological domains Acetylcholine Dopamine GABA Glutamate Histamine Ion channel Melatonin Norepinephrine Opioid Orexin Serotonin Table 2 9 Modes of action Enzyme inhibitor Enzyme modulator Ion channel blocker Neurotransmitters releaser Positive allosteric modulator Receptor agonist Receptor antagonist Receptor partial agonist Reuptake inhibitor
US Food and Drug Administration (FDA)-approved hypnotic medications fall into 5 families (TABLE 2(40)): benzodiazepines (BDZs), benzodiazepine agonists (BDZAs, sometimes called "Z drugs"), melatonin agonists (eg, ramelteon), tricyclic antidepressants (eg, low-dose doxepin), and orexin antagonists (eg, suvorexant).
Impaired orexin receptor expression in the Kolliker-Fuse nucleus in sudden infant death syndrome: possible involvement of this nucleus in arousal pathophysiology.
Therefore, in the Spinal Manipulation section, the sentence "Both cervical and thoracic groups saw decreases in neurotensin and oxytocin, as well as increases in orexin A plasma concentrations following respective interventions" should be corrected to "Both cervical and thoracic groups saw increases in neurotensin and oxytocin, as well as decreases in orexin A plasma concentrations following respective interventions."