Open AccessP2X receptors (version 2020.4) in the IUPHAR/BPS Guide to Pharmacology Database
Author(s) -
Francesco Di Virgilio,
Richard J. Evans,
Simonetta Falzoni,
Samuel J. Fountain,
Michael F. Jarvis,
Charles Kennedy,
Baljit S. Khakh,
Brian F. King,
Annette Nicke,
Patrizia Pellegatti,
John A. Peters
Publication year - 2020
Publication title -
iuphar/bps guide to pharmacology cite
Language(s) - English
Resource type - Journals
ISSN - 2633-1020
DOI - 10.2218/gtopdb/f77/2020.4
Subject(s) - receptor , agonist , chemistry , homomeric , class c gpcr , dorsal root ganglion , neuroscience , biology , metabotropic receptor , biochemistry , spinal cord , protein subunit , gene
P2X receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on P2X Receptors [48, 141]) have a trimeric topology [124, 139, 188] with two putative TM domains, gating primarily Na+, K+ and Ca2+, exceptionally Cl-. The Nomenclature Subcommittee has recommended that for P2X receptors, structural criteria should be the initial criteria for nomenclature where possible. X-ray crystallography indicates that functional P2X receptors are trimeric and three agonist molecules are required to bind to a single receptor in order to activate it [139, 93, 101, 170]. Native receptors may occur as either homotrimers (e.g. P2X1 in smooth muscle) or heterotrimers (e.g. P2X2:P2X3 in the nodose ganglion [265], P2X1:P2X5 in mouse cortical astrocytes [155], and P2X2:P2X5 in mouse dorsal root ganglion, spinal cord and mid pons [52, 221].P2X2, P2X4 and P2X7 receptor activation can also lead to influx of large cationic molecules, such as NMDG, Yo-Pro, ethidium or propidium iodide [200]. The hemi-channel pannexin-1 was initially implicated in the action of P2X7 [201], but not P2X2, receptors [40], but this interpretation is probably misleading. Convincing evidence now supports the view that the activated P2X7 receptor is immediately permeable to large cationic molecules, but influx proceeds at a much slower pace than that of the small cations Na+, K+, and Ca2+ [64].