TY - JOUR AU - Francesco Di Virgilio AU - Richard J. Evans AU - Simonetta Falzoni AU - Samuel J. Fountain AU - Michael F. Jarvis AU - Charles Kennedy AU - Baljit S. Khakh AU - Brian F. King AU - Annette Nicke AU - Patrizia Pellegatti AU - John A. Peters PY - 2020/09/24 Y2 - 2024/03/28 TI - P2X receptors (version 2020.4) in the IUPHAR/BPS Guide to Pharmacology Database JF - IUPHAR/BPS Guide to Pharmacology CITE JA - GtoPdb CITE VL - 2020 IS - 4 SE - Summaries DO - 10.2218/gtopdb/F77/2020.4 UR - http://journals.ed.ac.uk/gtopdb-cite/article/view/5057 AB - 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]. ER -