Coddou Claudio, Sandoval Rodrigo, Hevia María José, Stojilkovic Stanko S
Departmento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile; Section on Cellular Signaling, TheEunice Kennedy ShiverNational Institute of Health and Human Development, National Institutes of Health, Bethesda, MD 20892, United States.
Departmento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile.
Neurosci Lett. 2019 Jan 18;690:219-224. doi: 10.1016/j.neulet.2018.10.047. Epub 2018 Oct 23.
P2X receptors (P2XRs) are a family of ATP-gated ionic channels that are expressed in numerous excitable and non-excitable cells. Despite the great advance on the structure and function of these receptors in the last decades, there is still lack of specific and potent antagonists for P2XRs subtypes, especially for the P2X4R. Here, we studied in detail the effect of the P2X4R antagonist 5-(3-bromophenyl)-1,3-dihydro-2H-benzofuro[3,2-e]-1,4-diazepin-2-one (5-BDBD) on ATP-induced currents mediated by the rat P2X4R and compared its specificity among another rat P2XRs. We found that 5-BDBD is a potent P2X4R antagonist, with an IC of 0.75 μM when applied for 2 min prior and during ATP stimulation. Moreover, at 10 μM concentration, 5-BDBD did not affect the ATP-induced P2X2aR, P2X2bR, and P2X7R current amplitude or the pattern of receptor desensitization. However, at 10 μM concentration but not 0.75 μM 5-BDBD inhibited the P2X1R and P2X3R-gated currents by 13 and 35% respectively. Moreover, we studied the effects of 5-BDBD in long-term potentiation experiments performed in rat hippocampal slices, finding this antagonist can partially decrease LTP, a response that is believed to be mediated in part by endogenous P2X4Rs. These results indicate that 5-BDBD could be used to study the endogenous effects of the P2X4R in the central nervous system and this antagonist can discriminate between P2X4R and other P2XRs, when they are co-expressed in the same tissue.
P2X受体（P2XRs）是一类ATP门控离子通道家族，在众多可兴奋和不可兴奋细胞中均有表达。尽管在过去几十年中这些受体的结构和功能取得了巨大进展，但仍然缺乏针对P2XRs亚型，尤其是P2X4R的特异性强效拮抗剂。在此，我们详细研究了P2X4R拮抗剂5-（3-溴苯基）-1,3-二氢-2H-苯并呋喃[3,2-e]-1,4-二氮杂卓-2-酮（5-BDBD）对大鼠P2X4R介导的ATP诱导电流的影响，并比较了其在其他大鼠P2XRs中的特异性。我们发现5-BDBD是一种强效P2X4R拮抗剂，在ATP刺激前和刺激期间提前2分钟应用时，其IC50为0.75μM。此外，在10μM浓度下，5-BDBD不影响ATP诱导的P2X2aR、P2X2bR和P2X7R电流幅度或受体脱敏模式。然而，在10μM浓度而非0.75μM时，5-BDBD分别抑制P2X1R和P2X3R门控电流13%和35%。此外，我们研究了5-BDBD在大鼠海马切片长期增强实验中的作用，发现该拮抗剂可部分降低LTP，这种反应被认为部分由内源性P2X4Rs介导。这些结果表明，5-BDBD可用于研究P2X4R在中枢神经系统中的内源性作用，并且当该拮抗剂与其他P2XRs在同一组织中共表达时，它可以区分P2X4R和其他P2XRs。
