Dopamine Homeostasis, Vesicles & Neurodegeneration

多巴胺稳态，囊泡

• 批准号: 6320413
• 负责人: Patricia K Sonsalla
• 金额: $ 29.98万
• 依托单位: UNIV OF MED/DENT NJ-R W JOHNSON MED SCH
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6320413
• 关键词: amiodarone; amphetamines; cyanides; dopamine; ketanserin; laboratory mouse; laboratory rat; malonates; manganese; methylphenyltetrahydropyridine; neural degeneration; neurotoxins; oxidative stress; phenylephrine; plant insecticide; tissue /cell culture; transport proteins; verapamil; vesicle /vacuole

DESCRIPTION: (Verbatim from the Applicant's Abstract) Parkinson's disease is a debilitating motor impairment disorder due to loss of nigral dopamine neurons. Mitochondrial defects in PD patients implicate energy impairment and metabolic stress as potential factors in its etiology. Moreover, DA oxidation products may add to the oxidative burden within DA neurons which, coupled with a persistent metabolic stress, may lead to neurodegeneration. Epidemiological studies link PD with environmental exposure to substances such as pesticides. - Many pesticides are mitochondrial inhibitors. A potential form of protection against mitochondrial toxins (i.e., MPP+) may be their sequestration into synaptic vesicles of DA neurons. The goal of this project is to gain an understanding of the role of vesicles, the vesicular monoamine transporter (VMAT2) and DA in modulating neurodegeneration produced by mitochondrial toxins. One hypothesis is that the actions of mitochondrial toxins can be modulated in contrasting ways depending on whether the toxins are sequestered into vesicles. If sequestered, toxin exposure could be abrogated. In contrast, disruption of vesicular function toxin could lead to disturbed DA homeostasis and enhanced toxicity since it would remove the toxin from interaction with mitochondria. In Aim 1 several mitochondrial toxins will be examined for their ability to interfere with vesicle function (i.e. to inhibit DA uptake into isolated rat membrane vesicles). In aim 2, rat mesencephalic cultures or rat striata will be exposed to mitochondrial toxins following VMAT2 inhibition to determine if toxicity is modified. To examine the hypothesis that disturbed DA homeostasis contributes to degeneration produced by metabolic stress, two approaches will be used. First, DA will be depleted prior to exposure of culture or rat striata to a mitochondrial inhibitor. Second, vesicle contents (DA) will be released into the cytosol after exposure to the mitochondrial toxin to examine if augmented disruption of DA homeostasis during the metabolic stress enhances toxicity. Additionally, the hypothesis that substances that are not themselves mitochondrial inhibitors, but can disrupt DA storage in vesicles may amplify damage during episodes of metabolic stress will be examined in Aim 3. In aim 4 the hypothesis that early events such as oxidative stress leads to loss of vesicle function, disruption of DA homeostasis and exacerbation of neurodegeneration produced by toxins will be investigated. Isolated vesicles will be tested for their sensitivity to oxidizing and reducing conditions. Results from these studies will provide novel and relevant information as to the contribution of VMAT2 containing vesicles in neuroprotection as well as in neurodegeneration of DA neurons during metabolic stress.

描述：（申请人摘要的逐字病）帕金森氏病是一种 由于多巴胺神经元的丧失，使运动障碍障碍衰弱。 PD患者的线粒体缺陷暗示能量障碍和代谢 压力是其病因的潜在因素。此外，DA氧化产物 可能会增加DA神经元内的氧化负担 持续的代谢应激可能导致神经变性。流行病学 研究将PD与环境暴露与农药等物质联系起来。 - 许多农药是线粒体抑制剂。一种潜在的保护形式 针对线粒体毒素（即MPP+）可能是它们的隔离 DA神经元的突触囊泡。该项目的目的是获得 了解囊泡的作用，囊泡单胺转运蛋白 （VMAT2）和DA调节线粒体产生的神经变性 毒素。一个假设是线粒体毒素的作用可以是 根据是否隔离毒素，以相反的方式调节 进入囊泡。如果隔离，可以消除毒素的暴露。相比之下， 囊泡功能毒素的破坏可能导致DA稳态受到干扰 并增强毒性，因为它会使毒素与 线粒体。在目标1中，将检查几个线粒体毒素的 能够干扰囊泡功能的能力（即抑制DA的吸收 分离的大鼠膜囊泡）。在AIM 2中，大鼠中脑培养或大鼠 在VMAT2抑制后，纹状体将暴露于线粒体毒素 确定毒性是否被修饰。检查干扰DA的假设 稳态有助于代谢压力产生的变性，两个 将使用方法。首先，在暴露之前将耗尽DA 对线粒体抑制剂的培养或大鼠纹状体。其次，囊泡含量 （DA）将在暴露于线粒体后将其释放到细胞质中 毒素检查代谢过程中DA稳态的破坏是否增强 压力增强了毒性。另外，假设物质是 本身不是线粒体抑制剂，但会破坏囊泡中的da储存 可能会在AIM中检查在代谢压力发作期间放大损害 3。在目标4中的假设，即早期事件（例如氧化应激）导致 囊泡功能的丧失，DA稳态的破坏和加剧 将研究由毒素产生的神经变性。分离的囊泡 将测试其对氧化和还原条件的敏感性。 这些研究的结果将提供有关的新颖和相关信息 VMAT2在神经保护和中包含囊泡的贡献以及 代谢应激期间DA神经元的神经变性。