Contrary to common belief, not all vertebrates regulate their sleep-wake rhythm in the same way. University of Basel researchers have discovered that some fish—unlike humans—do not need orexin to stay awake. This molecule ...
Mar 14, 2024
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The way the brain regulates pupil size is different from previously thought: fundamentally responsible is the neurotransmitter orexin, as researchers at ETH Zurich have now shown. This discovery could well alter our understanding ...
Jul 13, 2023
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Rutgers researchers think they have identified a biological process for drug and alcohol addiction, and believe existing insomnia treatments could be used to reduce or eliminate cravings.
Nov 9, 2022
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Emmanuel Mignot is one of the world's leading experts on narcolepsy, a sleep disorder that he finds both "strange" and "fascinating."
Sep 22, 2022
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Neuropeptides play fundamental roles in modulating cellular and circuit functions within the brain. One such signaling molecule—orexin—regulates arousal and wakefulness, and its failure can lead to constant daytime sleepiness ...
Feb 10, 2022
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Sleep deprivation may pave the way to cocaine addiction. Too-little sleep can increase the rewarding properties of cocaine, according to new research in mice published in eNeuro.
Nov 2, 2020
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Researchers from the Bellvitge Biomedical Research Institute (IDIBELL) and the group of Eating Disorders, of the Bellvitge University Hospital (HUB), led by Dr. Fernando Fernández-Aranda, published a study in Scientific ...
Jun 12, 2019
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A study in cocaine-addicted rats reports long-lasting increases in the number of neurons that produce orexin—a chemical messenger important for sleep and appetite—that may be at the root of the addiction. The study, performed ...
Sep 12, 2018
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It's every over-achiever's dream: a gene mutation that allows them to function normally with just four to six hours of sleep a night instead of the normal eight.
Mar 19, 2018
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Narcolepsy, a serious sleep disorder in which patients often fall asleep uncontrollably, has been incurable because no effective therapeutic agents are available to date. Recent findings by Japanese scientists in the sleep ...
May 30, 2017
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Orexins, also called hypocretins, are the common names given to a pair of excitatory neuropeptide hormones that were simultaneously discovered by two groups of researchers in rat brains.
The two related peptides (Orexin-A and B, or hypocretin-1 and -2), with approximately 50% sequence identity, are produced by cleavage of a single precursor protein. Orexin-A/hypocretin-1 is 33 amino acid residues long and has two intrachain disulfide bonds, while Orexin-B/hypocretin-2 is a linear 28 amino acid residue peptide. Studies suggest that orexin A/hypocretin-1 may be of greater biological importance than orexin B/hypocretin-2. Although these peptides are produced by a very small population of cells in the lateral and posterior hypothalamus, they send projections throughout the brain. The orexin peptides bind to the two G-protein coupled orexin receptors, OX1 and OX2, with Orexin-A binding to both OX1 and OX2 with approximately equal affinity while Orexin-B binds mainly to OX2 and is 5 times less potent at OX1.
The orexins/hypocretins are strongly conserved peptides, found in all major classes of vertebrates.[citation needed]
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