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The orexinergic system, projecting from the lateral hypothalamus, operates through two receptors, orexin receptor type-1 (OX) and orexin receptor type-2 (OX), stabilizing wakefulness, mainly via OX. Narcolepsy Type 1 (NT1) is characterized by excessive sleepiness and cataplexy, and is linked to a loss of orexin-producing neurons. Current therapies manage the symptoms but do not address the underlying cause of the disease. For example, psychostimulants (e.g., modafinil) reduce excessive daytime sleepiness (EDS) and sodium oxybate (gammaaminobutyric acid receptor agonist) reduces both EDS and cataplexy. Despite decades of research, no small-molecule OX agonist has reached the market. This study presents the discovery of two new brain-penetrant, orally bioavailable OX agonists with a phenylglycine-like scaffold. These compounds stabilized wakefulness and reduced cataplexy in a mouse model of NT1. In healthy dogs, they increased time in wakefulness. These results highlight their potential as treatment for narcolepsy and other types of hypersomnolence.
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http://dx.doi.org/10.1021/acs.jmedchem.5c00362 | DOI Listing |
Front Neurosci
August 2025
Beijing Life Science Academy, Beijing, China.
Hypocretin, also known as orexin, is a hypothalamic neuropeptide that regulates essential physiological processes including arousal, energy metabolism, feeding behavior, and emotional states. Through widespread projections and two G-protein-coupled receptors-HCRT-1R and HCRT-2R-the hypocretin system exerts diverse modulatory effects across the central nervous system. The role of hypocretin in maintaining wakefulness is well established, particularly in narcolepsy type 1 (NT1), where loss of hypocretin neurons leads to excessive daytime sleepiness and cataplexy.
View Article and Find Full Text PDFEpilepsia
September 2025
Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, Nebraska, USA.
The rate of sudden unexpected death in epilepsy (SUDEP) is ~1 per 1000 patients each year. Terminal events reportedly involve repeated and prolonged apnea, suggesting a failure to autoresuscitate. To better understand the mechanisms and identify novel therapeutics, standardized tests to screen for autoresuscitation efficacy are needed in preclinical SUDEP.
View Article and Find Full Text PDFJ Psychopharmacol
September 2025
Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.
Rapid eye movement sleep (REMS) has historically been associated with anecdotal 'creative insights', possibly due to the fantastical and ostensibly illuminating nature of its associated phenomena (dreams). REMS, characterised by rapid eye movements, muscle atonia, and high-energy neuronal activity, has been linked to memory consolidation and information processing, particularly regarding the formation of novel associations or reintegration of consolidated memories into new cognitive networks. However, studies in these domains have largely used methodology which deprived subjects (animal or human) of REMS, rather than enhanced it.
View Article and Find Full Text PDFExpert Opin Pharmacother
September 2025
Department of Psychiatry, University of Calgary, Calgary, Alberta.
Introduction: Cannabis use disorder (CUD) is a growing global health concern, with limited pharmacological treatments currently available despite increasing prevalence and legalization trends.
Areas Covered: This review explores the landscape of pharmacotherapies for CUD, including both repurposed agents and emerging investigational compounds. We summarize findings from recent systematic reviews and meta-analyses, with attention to mechanisms of action and clinical relevance.
Pharmacol Res Perspect
October 2025
Department of Nutritional Sciences, University of Georgia, Athens, Georgia, USA.
Exogenous cannabinoids have long been known to promote eating. However, the underlying mechanisms have not been completely elucidated, which is critical to understanding their utility. The orexin/hypocretin (OH) system of the lateral hypothalamus (LHA) has known anatomical, biochemical, and physiological interactions with the endocannabinoid system, and has an established role in promoting appetitive behavior; yet, it is still unknown if the OH system mediates food intake following cannabinoid administration.
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