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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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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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 is a disorder caused by losing orexin neurons, marked by excessive daytime sleepiness and cataplexy, and sudden weakening of muscle control. Previously, we found two kinds of neurons preventing narcolepsy by receiving ...
May 15, 2017
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A team of American and Italian neuroscientists has identified a cellular change in the brain that accompanies obesity. The findings could explain the body's tendency to maintain undesirable weight levels, rather than an ideal ...
Apr 29, 2013
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The fat we typically think of as body fat is called white fat. But there's another type—known as brown fat—that does more than just store fat. It burns fat. Scientists used to think that brown fat disappeared after ...
Oct 4, 2011
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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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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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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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