Mechanistic studies of the GYKI Compounds

描述（由申请人提供）：嗜离子性谷氨酸受体的1-氨基-3-羟基-5-甲基-4-异唑丙酸（AMPA）亚型的过度激活已被认为是许多神经系统疾病的主要诱因，如癫痫、中风和肌萎缩侧索硬化症（ALS）。使用抑制剂作为神经保护药物来抑制过度的受体活性是一种长期追求的治疗策略。2,3-苯二氮卓类衍生物，也被称为GYKI化合物，是AMPA受体的抑制剂，它们代表了迄今为止开发的一类最有前途的候选药物。然而，这些化合物在AMPA受体上的数量和功能活性仍然不明确。这是因为AMPA受体在微秒时间域打开通道，即使在毫秒时间域也会脱敏。然而，目前的动力学技术没有足够的时间分辨率来表征通道打开的动力学机制和抑制剂/药物-受体相互作用的机制。在本论文中，我们将系统地阐明一系列19种GYKI化合物的作用机制，测量它们在特定AMPA受体亚基上的效力，并表征其结构-活性关系，包括受体上的抑制位点数量以及是否有两个位点相互作用（即，两个抑制剂与它们位点的结合可能是独立的，也可能被其中一个先结合而产生负面影响）。为了实现具体目标，我们将进行一系列实验，包括激光脉冲光解研究与？研究GYKI化合物对AMPA受体通道打开速率过程的影响。这些化合物的动力学研究，与所有受体形式仍然具有功能的时间尺度有关，以前是不可能的。这些化合物的受体性质和构效关系的研究结果将为合理设计和合成具有亚基选择性和构象选择性的高效GYKI化合物，从而更定量地控制AMPA受体的活性提供参考。公共卫生相关性：我们建议系统地表征一组GYKI化合物，它们是AMPA谷氨酸离子通道受体的抑制剂。这些化合物是开发潜在药物来治疗涉及AMPA受体的许多神经系统疾病的候选者。

DESCRIPTION (provided by applicant): Excessive activation of the 1-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) subtype of ionotropic glutamate receptors has been implicated as a leading contributor to a number of neurological diseases, such as epilepsy, stroke and amyotrophic lateral sclerosis (ALS). Using inhibitors as neuroprotective drugs to dampen the excessive receptor activity has been a long pursued therapeutic strategy. 2,3-Benzodiazepine derivatives, also known as GYKI compounds, are inhibitors of AMPA receptors, and they represent a class of the most promising drug candidates developed to date. However, the quantitative, functional activities of these compounds on AMPA receptors remain poorly defined. This is because AMPA receptors open their channels in the microsecond time domain and desensitize even in the millisecond time region. Yet, current kinetic techniques do not have sufficient time resolutions required to characterize the kinetic mechanism of channel opening and the mechanism of inhibitor/drug- receptor interaction. In this proposal, we will systematically elucidate the mechanism of action for a series of 19 GYKI compounds, measure their potency on specific AMPA receptor subunits, and characterize the structure-activity relationship, including the number of inhibitory sites on a receptor and whether any two sites interact with each other (i.e., the binding of two inhibitors to their sites can be independent or negatively affected by binding of either one first). To achieve the specific aims, we will carry out a number of experiments, including a laser- pulse photolysis study with the ?s time resolution to investigate the effect of a GYKI compound on the channel-opening rate process of an AMPA receptor. The kinetic investigation of these compounds, relevant to the time scale within which all receptor forms are still functional, has not been previously possible. Our results on the receptor properties and the structure-activity relationship of these compounds will be valuable for rational design and synthesis of subunit- and conformation-selective GYKI compounds with higher potency so that AMPA receptor activities can be controlled more quantitatively. PUBLIC HEALTH RELEVANCE: We propose to systematically characterize a group of GYKI compounds, which are inhibitors on AMPA glutamate ion channel receptors. These compounds are candidates for developing potential drugs to treat a number of neurological diseases involving AMPA receptors.