Virginio C, Robertson G, Surprenant A, North R A
Geneva Biomedical Research Institute, Glaxo Wellcome Research and Development, Geneva, 1228 Switzerland.
Mol Pharmacol. 1998 Jun;53(6):969-73.
There are currently seven P2X receptor subunits (P2X1-7) defined by molecular cloning. The functional identification of these receptors has relied primarily on the potency of alpha,beta-methylene-ATP relative to that of ATP and on the kinetics of receptor desensitization. In the present experiments we found that the 2', 3'-O-(2,4,6-trinitrophenyl)-substituted analogs of ATP are selective and potent antagonists at some but not all P2X receptors. The trinitrophenyl analogs of ATP, ADP, AMP, and GTP produced a reversible inhibition of ATP-evoked currents in human embryonic kidney 293 cells expressing P2X1 receptors, P2X3 receptors, or both P2X2 and P2X3 (heteromeric) receptors; IC50 values were close to 1 nM. These compounds were at least 1000-fold less effective in blocking currents in cells expressing P2X2, P2X4, or P2X7 receptors (P2X5 and P2X6 not tested). GTP, 2,4,6-trinitrophenol, and the 2',3'-trinitrophenyl analog of adenosine (0.1-10 microM) had no effect. Thus, we have identified a structural motif that confers antagonist action at P2X receptors that contain P2X1 or P2X3 subunits (the alpha,beta-methylene-ATP-sensitive subclass).
目前通过分子克隆已确定有7种P2X受体亚基（P2X1 - 7）。这些受体的功能鉴定主要依赖于α,β - 亚甲基 - ATP相对于ATP的效力以及受体脱敏的动力学。在本实验中，我们发现ATP的2', 3'-O -（2,4,6 - 三硝基苯基）取代类似物是某些但并非所有P2X受体的选择性强效拮抗剂。ATP、ADP、AMP和GTP的三硝基苯基类似物对表达P2X1受体、P2X3受体或P2X2和P2X3（异源二聚体）受体的人胚肾293细胞中ATP诱发的电流产生可逆性抑制；IC50值接近1 nM。这些化合物对表达P2X2、P2X4或P2X7受体的细胞（未测试P2X5和P2X6）中的电流阻断作用至少低1000倍。GTP、2,4,6 - 三硝基苯酚和腺苷的2',3'-三硝基苯基类似物（0.1 - 10 microM）无作用。因此，我们鉴定出一种结构基序，其赋予含有P2X1或P2X3亚基的P2X受体（α,β - 亚甲基 - ATP敏感亚类）拮抗剂作用。
