North R A, Barnard E A
Geneva Biomedical Research Institute, Glaxo Wellcome Research and Development, 14 chemin des Aulx, Plan-les-Ouates, 1228 Geneva, Switzerland.
Curr Opin Neurobiol. 1997 Jun;7(3):346-57. doi: 10.1016/s0959-4388(97)80062-1.
Adenosine 5'-triphosphate (ATP) and/or related nucleotides act at both ionotropic (P2X) and metabotropic (P2Y) receptors. P2X receptor subunits (P2X1-P2X7) form ligand-gated cation channels, as homomultimers or heteromultimers. Recent work indicates that P2X3 subunits participate in channels expressed by nociceptive sensory neurons, and that the second of the two transmembrane domains of each subunit contributes to the ion permeation pathway. P2X7 subunits form large cytolytic pores in addition to cation channels; they have been found in macrophages and brain microglia. P2Y receptors form a distinct subset of G-protein-coupled receptors; most couple through G proteins to phospholipase C, but inhibition of adenylate cyclase and N-type Ca2+ channels, and activation of K+ channels also occurs. Expressed P2Y receptors have generally been distinguished pharmacologically by the rank order of effectiveness of agonists; some prefer pyrimidines to purines. Recent studies suggest that it is important to use purified nucleotides in such classifications. Several P2Y receptors have a very widespread tissue distribution.
5'-三磷酸腺苷（ATP）和/或相关核苷酸作用于离子型（P2X）和代谢型（P2Y）受体。P2X受体亚基（P2X1 - P2X7）作为同多聚体或异多聚体形成配体门控阳离子通道。最近的研究表明，P2X3亚基参与伤害性感觉神经元表达的通道，并且每个亚基的两个跨膜结构域中的第二个结构域参与离子渗透途径。P2X7亚基除了形成阳离子通道外，还形成大的溶细胞孔；它们已在巨噬细胞和脑小胶质细胞中被发现。P2Y受体构成G蛋白偶联受体的一个独特亚群；大多数通过G蛋白与磷脂酶C偶联，但也会发生腺苷酸环化酶和N型Ca2+通道的抑制以及K+通道的激活。表达的P2Y受体通常通过激动剂有效性的排序在药理学上加以区分；一些受体对嘧啶的偏好高于嘌呤。最近的研究表明，在这种分类中使用纯化的核苷酸很重要。几种P2Y受体具有非常广泛的组织分布。
