A Novel <i>N</i>-Methyl-d-aspartate Receptor Open Channel Blocker with in Vivo Neuroprotectant Activity
作者:Rosa Planells-Cases、Carmina Montoliu、Marc Humet、Asia M. Fernández、Carolina Garcı́a-Martı́nez、Elvira Valera、Jaime M. Merino、Enrique Pérez-Payá、Angel Messeguer、Vicente Felipo、Antonio Ferrer-Montiel
DOI:10.1124/jpet.302.1.163
日期:2002.7.1
Excitotoxicity has been implicated in the etiology of ischemic stroke, chronic neurodegenerative disorders, and very recently, in glioma growth. Thus, the development of novel neuroprotectant molecules that reduce excitotoxic brain damage is vigorously pursued. We have used an ionic current block-based cellular assay to screen a synthetic combinatorial library of trimers of N -alkylglycines on the N -methyl-d-aspartate (NMDA) receptor, a well known molecular target involved in excitotoxicity. We report the identification of a family of N -alkylglycines that selectively blocked the NMDA receptor. Notably, compound 3,3-diphenylpropyl- N -glycinamide (referred to as N20C) inhibited NMDA receptor channel activity with micromolar affinity, fast on-off blockade kinetics, and strong voltage dependence. Molecule N20C did not act as a competitive glutamate or glycine antagonist. In contrast, saturation of the blocker binding site with N20C prevented dizolcipine (MK-801) blockade of the NMDA receptor, implying that both drugs bind to the same receptor site. The N -alkylglycine efficiently prevented in vitro excitotoxic neurodegeneration of cerebellar and hippocampal neurons in culture. Attenuation of neuronal glutamate/NMDA-induced Ca2+ overload and subsequent modulation of the glutamate-nitric oxide-cGMP pathway seems to underlie N20C neuroprotection. Noteworthy, this molecule exhibited significant in vivo neuroprotectant activity against an acute, severe, excitotoxic insult. Taken together, these findings indicate that N -alkylglycine N20C is a novel, low molecular weight, moderate-affinity NMDA receptor open channel blocker with in vitro and in vivo neuroprotective activity, which, in due turn, may become a tolerated drug for the treatment of neurodegenerative diseases and cancer.
兴奋毒性与缺血性中风、慢性神经退行性疾病的病因有关,最近还与胶质瘤的生长有关。因此,减少兴奋性毒性脑损伤的新型神经保护剂分子的开发受到了极大的关注。我们使用了一种基于离子电流阻滞的细胞测定法,筛选出了N-甲基-d-天冬氨酸(NMDA)受体上的N-烷基甘氨酸三聚体的合成组合库,NMDA受体是一种众所周知的参与兴奋毒性的分子靶点。我们报告了一系列选择性阻断 NMDA 受体的 N -烷基甘氨酸的鉴定结果。值得注意的是,化合物 3,3-二苯基丙基-N-甘氨酰胺(简称 N20C)以微摩尔亲和力、快速通断阻断动力学和强电压依赖性抑制 NMDA 受体通道活性。分子 N20C 并非竞争性谷氨酸或甘氨酸拮抗剂。相反,N20C 与阻断剂结合位点的饱和可阻止地佐西平(MK-801)对 NMDA 受体的阻断,这意味着这两种药物与相同的受体位点结合。N -烷基甘氨酸能有效防止体外培养的小脑和海马神经元的兴奋毒性神经变性。减轻神经元谷氨酸/NMDA 诱导的 Ca2+ 过载以及随后对谷氨酸-一氧化氮-GMP 途径的调节似乎是 N20C 神经保护作用的基础。值得注意的是,这种分子对急性、严重的兴奋性毒性损伤具有显著的体内神经保护活性。综上所述,这些研究结果表明,N-烷基甘氨酸 N20C 是一种新型、低分子量、中等亲和力的 NMDA 受体开放通道阻滞剂,具有体外和体内神经保护活性,它有可能成为治疗神经退行性疾病和癌症的耐受性药物。