CHOLINERGIC MECHANISMS IN AGING AND ALZHEIMER'S DISEASE

衰老和阿尔茨海默病的胆碱能机制

• 批准号: 3117036
• 负责人: Lincoln T. Potter
• 金额: $ 16.43万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-05-01 至 1991-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3117036
• 关键词: Alzheimer's disease; acetylcholinesterase; aging; autoradiography; cerebral cortex; choline acetyltransferase; denervation; dosage; estradiol; gel electrophoresis; guanine nucleotides; hippocampus; histopathology; human tissue; membrane structure; microscopy; neurochemistry; neuropharmacology; nicotine; parasympathetic nervous system; synapses

The proposed research concerns the status of cholinergic synapses in the cerebral cortex during aging and the progression of Alzheimer's disease (AD), studies of normal and altered neurochemical mechanisms of pre- and postsynaptic muscarine receptors, and measurements with agents which may prevent or reverse cholinergic dysfunction in aging and AD. Seven aims are proposed. In aim I, new assays for presynaptic M2 and postsynaptic M1 and nicotine receptors will be used to assess these sited in 7 bilateral cortical regions of normal, aged and AD human brains, for the first time. It is likely that an increasing M1/M2 ratio will correlate closely with increasing neuropathology, and prove to be a useful neurochemical measure of cholinergic denervation. The same brains and regions will be used in aim 2 to compare the laminar cortical patterns of declining M2 receptors, increasing neuritic plaques, and remaining postsynaptic receptors, by silver-staining and new autoradiographic (AR) techniques. These studies test hypotheses that changes in cholinergic synapses may be an invariant feature of AD, and that they correlate spatially and temporally with the appearance of plaques as AD progresses. A library of tissue blocks will be obtained for future work with other kinds of synapses. In aim 3, the efficacy of various M1-agonists will be estimated from their ability to promote a GppNHp-sensitive high affinity state of these receptors, both for aim 7 and for possible AD therapy. Effective M1-agonists have not yet been tried in AD. In aim 4, the conditions necessary for estradiol to upregulate cortical cholinergic nerves will be explored in rats, using sex, time, dose and age as variables. Long term goals include trials of estradiol to prevent changes in cholinergic synapses in aging animals and AD. Aim 5 explores downregulation of nicotine receptors in the rat cortex with respect to nicotine dosage and timing. The intent is to see whether these receptors can be repeatedly activated without causing desensitization. Aim 6 concerns the reason for a major loss of high affinity agonist binding to cortical M2 receptors in old Fisher 344 rats, despite normal M2 levels. Pertussis toxin-catalyzed 32-ADP-ribosylation will be used to assess levels of a guanine nucleotide binding protein (Gi) associated with M2, and attempts will be made to stabilize altered agonist-M2-Gi ternary complexes for further studies. Aim 7 is an attempt to isolate and identify the nucleotide binding proteins associated specifically with rabbit brain M1 and M2, via soluble ternary complexes of each. Long term goals include detailed neurochemical work with the M1 postsynaptic mechanism, which promotes phosphoinositide metabolism and changes in cytosolic calcium, and may control growth.

拟议的研究涉及胆碱能突触的地位， 大脑皮层在老化和阿尔茨海默病的进展 (AD)，研究正常和改变的神经化学机制的前和 突触后毒蕈碱受体，以及用可 预防或逆转衰老和AD中的胆碱能功能障碍。 七个目标是 提出了 在目标I中，对突触前M2和突触后M1以及突触后M2的新测定方法被用于研究突触后M1的表达。 尼古丁受体将被用来评估这些网站在7双边 正常、老年和AD人脑的皮质区域，这是第一次。 M1/M2比率的增加可能与以下因素密切相关： 增加神经病理学，并证明是一个有用的神经化学措施 胆碱能去神经 同样的大脑和区域将被用于 目的2比较M2受体下降的皮层模式， 增加神经炎斑块和残留的突触后受体， 银染和新的放射自显影（AR）技术。 这些研究 测试假设，胆碱能突触的变化可能是一个不变的 他们在时间和空间上都有自己的特点， 随着AD的进展出现斑块。 组织块库将 为将来研究其他种类的突触做准备。 在目标3中， 各种M1-激动剂的功效将从它们 促进这些受体的GppNHp敏感的高亲和力状态， 目的7和可能的AD治疗。 有效的M1激动剂尚未被发现。 在AD中尝试 在目标4中，提供了雌二醇 上调皮质胆碱能神经将在大鼠中探索，使用性别， 时间、剂量和年龄作为变量。 长期目标包括试验 雌二醇，以防止衰老动物中胆碱能突触的变化， AD. 目的5探索大鼠皮质尼古丁受体的下调 尼古丁的剂量和时间 目的是看看是否 这些受体可以被反复激活， 脱敏 目标6是关于高价值资产重大损失的原因。 在老年Fisher 344大鼠中与皮质M2受体结合的亲和激动剂， 尽管M2水平正常 百日咳毒素催化的32-ADP-核糖基化反应 将用于评估鸟嘌呤核苷酸结合蛋白（Gi）的水平 与M2相关，并试图稳定改变的 激动剂-M2-Gi三元复合物用于进一步研究。 Aim 7是一种尝试 分离并鉴定与之相关的核苷酸结合蛋白 特别是兔脑M1和M2，通过可溶性三元复合物， 每个. 长期目标包括详细的神经化学工作与M1 突触后机制，促进磷酸肌醇代谢， 细胞质钙的变化，并可能控制生长。