Definition
Orexin-A (OX-A) and Orexin-B (OX-B) are two pleiotropic bioactive neuropeptides encoded by a common prepro-hypocretin precursor gene (HCRT). Both peptides bind with differential affinity to two G protein–coupled receptors of the Gaq/11 family (Orexin receptors, OX1R, OX2R), each encoded by a separate gene (Hypocretin receptors, HCRTR1, HCRTR2). “HCRT” is the standard gene symbol and “OX” refers to the pharmacology of the peptides in accordance with the nomenclature of the International Union of Basic and Clinical Pharmacology. Orexin peptides are almost exclusively expressed in a small subset of hypothalamic neurons of the vertebrate brain (Fig. 2). In contrast, orexin receptors exhibit differential expression, signaling (Fig. 1, Table 1), pharmacology (Fig. 3, Table 2), and functions inside and outside the nervous system.
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Selbach, O. (2021). Orexins. In: Offermanns, S., Rosenthal, W. (eds) Encyclopedia of Molecular Pharmacology. Springer, Cham. https://doi.org/10.1007/978-3-030-21573-6_208-1
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DOI: https://doi.org/10.1007/978-3-030-21573-6_208-1
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