SIGMA RECEPTOR SIGNALING IN FOCAL CEREBRAL ISCHEMIA

局灶性脑缺血中的 Sigma 受体信号转导

• 批准号: 6273690
• 负责人: JEFFREY R KIRSCH
• 金额: $ 15.24万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6273690
• 关键词: G protein; autoradiography; biological signal transduction; brain disorder chemotherapy; brain metabolism; cerebral ischemia /hypoxia; dopamine; drug receptors; excitatory aminoacid; immunocytochemistry; laboratory mouse; laboratory rat; ligands; microdialysis; neurochemistry; neuroprotectants; nitric oxide synthase; nonhuman therapy evaluation; piperidine; reperfusion

Excitatory amino acids are an integral part of ischemic brain injury mechanisms. Because sigma-receptor ligands modulate neuronal responses to pharmacologic N-methyl D-aspartate (NMDA) receptor stimulation in vitro via a specific sigma ligand recognition site, they are of potential therapeutic value in stroke and may not be associate with the same spectrum of undesired side-effects which limit the clinical utility of NMDA receptor antagonists 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP) is a prototypic sigma- receptor ligand which provides neuroprotection but the exact mechanism of protection has not been previously elicited in vivo. Conclusions from in vitro experiments have suggested that sigma-receptor ligands may interfere with excitatory amino acid-induced neurotoxicity by interacting with the NMDA receptor complex. Further, sigma-receptor ligands may advantageously decrease excitotoxic neurotransmitter and catecholamine release during ischemia, specifically glutamate and dopamine. The overall goal of this project is to define the in vivo signaling process that accounts for the marked neuroprotective properties of sigma-receptor ligands in transient focal ischemia. The general hypothesis is that these ligands protect the brain by a unique sigma-receptor pathway which inhibits excitotoxin release and NMDA activation, and, therefore, prevents consequent neuronal nitric oxide synthase (nNOS) activation and cell death. The specific aims will: define the most efficacious treatment paradigm sigma-receptor ligand, PPBP, in transient focal ischemia; determine if sigma-receptor activation inhibits excitotoxic mechanisms of focal ischemic brain injury; characterize basal and post-ischemic sigma-receptor signaling mechanisms in vivo; determine if sigma receptor mediated mechanisms of neuroprotection are specific to the constitutive neuronal isoform of NOS. The methodology will include use of an intravascular thread occlusion model of transient focal ischemia in rodents (both rats and mice), microdialysis measurement of spontaneous and NMDA-stimulated NOS activity, microdialysis measurement of excitatory amino acids and dopamine with its metabolites, immunochemistry for detection of G-protein and autoradiography for measurement of sigma-receptor distribution. These techniques are combined to test the hypothesis that sigma-receptor ligands improve neurologic outcome (histology and neurologic function) by interfering with excitatory amino acid mechanisms during ischemia and reperfusion through a G-protein second messenger, all which ultimately result in decreased production of NO and decreased brain injury.

兴奋性氨基酸是缺血性脑损伤的组成部分 机制。因为Sigma受体配体调节对神经元反应 药理学N-甲基D-天冬氨酸（NMDA）受体刺激体外 通过特定的Sigma配体识别位点，它们具有潜力 中风的治疗价值，可能与同一 不希望的副作用的光谱限制了临床实用性 NMDA受体拮抗剂 4-苯基-1-（4-苯基丁基）哌啶（PPBP）是一种原型Sigma- 受体配体提供神经保护，但是确切的机制 以前尚未在体内引起保护。结论来自 体外实验表明Sigma受体配体可能会干扰 与兴奋性氨基酸诱导的神经毒性通过与 NMDA受体复合物。此外，Sigma受体配体可能有利 减少兴奋性神经递质和儿茶酚胺在期间释放 缺血，特别是谷氨酸和多巴胺。总体目标 项目是定义说明的体内信号传导过程 Sigma受体配体在瞬态中的明显神经保护特性 局灶性缺血。一般假设是这些配体保护 大脑通过独特的Sigma受体途径，该途径抑制兴奋毒素 释放和NMDA激活，因此可以防止随之而来的神经元 一氧化氮合酶（NNOS）激活和细胞死亡。具体目标 意愿：定义最有效的治疗范例Sigma受体 配体PPBP，瞬时局灶性缺血；确定Sigma受体是否受体 激活抑制局灶性缺血性脑损伤的兴奋性机制； 表征基础和缺血后的Sigma受体信号传导机制 体内;确定Sigma受体介导的机制是否 神经保护特定于NOS的组成型神经元同工型。 该方法将包括使用血管内螺纹遮挡 啮齿动物（大鼠和小鼠）中瞬时局灶性缺血模型， 自发性和NMDA刺激的NOS活性的微透析测量， 兴奋性氨基酸和多巴胺的微透析测量 代谢物，G蛋白检测的免疫化学和 用于测量Sigma受体分布的放射自显影。这些 将技术合并以测试Sigma受体配体的假设 通过通过 干扰缺血期间的兴奋性氨基酸机制 通过G蛋白第二使者再灌注，最终都是 导致NO和脑损伤减少的产生减少。