Dopamine Homeostasis, Vesicles & Neurodegeneration

多巴胺稳态，囊泡

• 批准号: 6718954
• 负责人: Patricia K Sonsalla
• 金额: $ 30.72万
• 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 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6718954
• 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：（逐字引用申请人的摘要）帕金森病是一种 由于黑质多巴胺神经元的丧失而导致的衰弱性运动障碍。 PD患者的线粒体缺陷与能量障碍和代谢紊乱有关 压力是其病因学中的潜在因素。此外，DA氧化产物 可能会增加DA神经元内的氧化负荷，再加上 持续的代谢压力，可能导致神经退化。流行病学 研究将PD与环境暴露于杀虫剂等物质联系起来。 - 许多农药是线粒体抑制剂。一种潜在的保护形式 对抗线粒体毒素（即，MPP+）可能是它们被螯合到 DA神经元的突触囊泡。该项目的目标是获得一个 了解囊泡的作用，囊泡单胺转运蛋白 （VMAT2）和DA在调节由线粒体引起的神经变性中的作用 毒素一种假设是，线粒体毒素的作用可以是 根据毒素是否被隔离 变成囊泡如果被隔离，毒素接触就可以被消除。与此相反， 毒素破坏囊泡功能可导致DA稳态紊乱 并增强毒性，因为它可以消除毒素与 线粒体在目标1中，将检查几种线粒体毒素的 干扰囊泡功能的能力（即抑制DA摄取到 分离的大鼠膜囊泡）。在目标2中，大鼠中脑培养物或大鼠 在VMAT2抑制后，纹状体将暴露于线粒体毒素， 确定毒性是否改变。为了验证一个假设， 体内平衡有助于代谢应激产生的退化， 将使用的方法。首先，DA将在暴露于 培养物或大鼠纹状体对线粒体抑制剂的作用。第二，囊泡内容物 (DA)将在暴露于线粒体后释放到胞质溶胶中 毒素，以检查代谢过程中是否增加了DA稳态的破坏 压力会增强毒性。此外，假设物质是 本身不是线粒体抑制剂，但可以破坏囊泡中的DA储存 可能会在代谢应激发作期间放大损伤，这将在Aim中进行研究。 3.在aim 4中，假设早期事件如氧化应激导致 囊泡功能丧失、DA稳态破坏和脑缺血加重 将研究由毒素产生的神经变性。孤立囊泡 将测试它们对氧化和还原条件的敏感性。 这些研究的结果将提供新的相关信息， 含有VMAT2的囊泡在神经保护以及在神经保护中的作用。 代谢应激期间DA神经元的神经变性。