METABOLISM AND NEUROTOXICITY STUDIES OF MPTP ANALOGS

我们建议研究代谢的命运和神经毒理学。 一系列与结构相关的化合物的性质 帕金森病致神经毒素1-甲基-4-- 苯基-1，2，3，6-四氢吡啶(MPTP) 对猴子(苯氧基四氢吡啶1和吡咯)的影响 取代4-哌啶酚4)，在人中[4-对氯苯基取代 4-哌啶醇氟哌啶醇(5)]或在小鼠体内(1-甲基吡咯基-2-基 MPTP的模拟3)。基于记录在案的MPTP的作用机制， 这些研究将集中在新陈代谢的形成和中枢神经系统的通路。 相应的吡啶属物种，潜在的终极神经毒素。全 测试化合物中的一种是部分氧化的哌啶衍生物，它 预计中间亚胺离子代谢物将经历 自发氧化为相应的吡啶物种。这个 测试化合物的神经毒性特性将由经典的 小鼠神经递质耗竭和组织病理学研究。在……里面 除了标准的染色技术外，我们还将使用免疫细胞化学 染色以确定可能涉及特定病变的特定病变 神经递质系统。这些研究不会局限于 多巴胺能系统，因为吡啶类化合物似乎普遍 神经毒性，特异性依赖于转运蛋白 本地化。预期的吡啶代谢物的毒性将 直接脑内注射或脑内注射后进行评估 微透析法灌流。这些吡啶类化合物能力的研究 抑制线粒体呼吸的化合物，这显然是必须采取的步骤 在其吡啶代谢物介导MPTP神经毒性的过程中， 将在细胞培养中借助一种基于超生命的染料进行研究 一种使用荧光光谱检测器的化验方法，它可以 随着时间的推移，线粒体在单个细胞或一组细胞中发挥作用。这 多学科计划将受益于以下几个方面的投入 顾问的主要研究活动依赖于拟议的 技巧。氟哌啶醇的初步结果，其 四氢吡啶衍生物及其相应的吡啶衍生物 支持这项提案的主要论点，即部分 氧化的1，4-二取代哌啶衍生物将被生物转化为 可进入中枢神经的神经毒性吡啶代谢物 系统。

We propose to investigate the metabolic fate and neurotoxicological properties of a series of compounds that are structurally related to the Parkinsonian inducing neurotoxin 1-methyl-4-- phenyl-1,2,3,6-tetrahydropyridine (MPTP) and which display neurotoxic effects in the monkey (the phenoxytetrahydropyridine 1 and pyrrole substituted 4-piperidinol 4), in man [the 4-pchlorophenyl substituted 4-piperidinol haloperidol (5)] or in the mouse (the 1-methylpyrrol-2-yl analog 3 of MPTP). Based on the documented mechanism of action of MPTP, these studies will focus on the metabolic formation and CNS access of the corresponding pyridinium species, the potential ultimate neurotoxins. All of the test compounds are partially oxidized piperidine derivatives and it is anticipated that the intermediate iminium ion metabolites will undergo spontaneous oxidation to the corresponding pyridinium species. The neurotoxic properties of the test compounds will be evaluated by classical neurotransmitter depletion and histopathology studies in the mouse. In addition to standard staining techniques, we will use immunocytochemical stains to identify specific lesions that may involve a particular neurotransmitter system. These studies will not be limited to the dopaminergic system since pyridinium derivatives appear to be generally neurotoxic with specificity being dependent on transporter based localization. The toxicity of the anticipated pyridinium metabolites will be assessed following direct intracerebral injection or intracerebral perfusion by microdialysis. Studies on the ability of these pyridinium compounds to inhibit mitochondrial respiration, an apparent obligatory step in the mediation of the neurotoxicity of MPTP by its pyridinium metabolite, will be investigated in cell culture with the aid of a supravital dye based assay which employs a spectrofluorometric detector that can estimate mitochondrial function in a single cell or group of cells over time. This multidisciplinary program will benefit from the input of several consultants whose principal research activities rely on the proposed techniques. Preliminary results obtained with haloperidol, its tetrahydropyridine derivative and the corresponding pyridinium derivative support the principal thesis of this proposal, namely that partially oxidized 1,4-disubstituted piperidine derivatives will be biotransformed to neurotoxic pyridinium metabolites that have access to the central nervous system.