CHOLINERGIC MECHANISMS IN AGING AND ALZHEIMER'S DISEASE

这项拟议的研究涉及胆碱能突触在脑内的地位。 大脑皮质衰老与阿尔茨海默病的进展 (AD)，Pre和Pre的正常和改变的神经化学机制的研究 突触后M受体，以及使用可能 预防或逆转衰老和阿尔茨海默病的胆碱能功能障碍。七个目标是 建议。在Aim I中，突触前M2和突触后M1和 尼古丁受体将被用来评估7个双侧的位置 首次对正常、衰老和阿尔茨海默病人脑的皮质区域进行了研究。 增加的M1/M2比率很可能与 增加神经病理学，并被证明是一种有用的神经化学措施 胆碱能神经丧失的症状。同样的大脑和区域将被用于 目的2比较递减M2受体的层流皮质模式， 增加神经元斑块和剩余的突触后受体，通过 银染和新的放射自显影(AR)技术。这些研究 胆碱能突触的变化可能是一个不变量的测试假设 AD的特征，并且它们在空间和时间上与 随着AD的进展，斑块的出现。一个组织块库将是 为将来研究其他类型的突触而获得。在目标3中， 各种M1激动剂的疗效将通过它们的能力来评估 促进这些受体对GppNHp敏感的高亲和力状态， 目标7和可能的AD治疗。有效的M1激动剂尚未被 在公元后尝试过。在目标4中，雌二醇达到 将在大鼠身上探索上调的皮质胆碱能神经，使用性， 以时间、剂量和年龄为变量。长期目标包括试验 雌二醇预防衰老动物胆碱能突触的变化 广告。目的5探索大鼠大脑皮质尼古丁受体的下调 关于尼古丁的剂量和时机。其目的是想看看是否 这些受体可以被重复激活而不会引起 脱敏。AIM 6关注HIGH的重大损失的原因 亲和激动剂与老年Fisher 344大鼠皮质M2受体结合， 尽管M2水平正常。百日咳毒素催化的32-ADP-核糖基化 将用于评估鸟嘌呤核苷酸结合蛋白(GI)的水平 与M2相关，并将尝试稳定改变 激动剂-M2-GI三元络合物有待进一步研究。Aim 7是一种尝试 分离和鉴定相关的核苷酸结合蛋白 特别是与兔脑M1和M2通过可溶的三元络合物 每个人。长期目标包括与M1进行详细的神经化学工作 突触后机制，促进磷脂酰肌醇代谢和 细胞内钙离子的变化，并可能控制生长。

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.