CHOLINERGIC REPLACEMENT THERAPY

拟议工作的目标是提供一个合理的 记忆胆碱能替代疗法的科学基础 疾病，特别是阿尔茨海默病（AD）。 这一目标 基于两个密切相关的主题。 首先，M1 毒蕈碱受体机制值得深入研究， 因为M1受体主要定位在 前脑，似乎对正常的大脑兴奋至关重要， 短期记忆，并没有得到很好的研究。 第二 使用M1激动剂的胆碱能疗法是最好的 治疗AD的希望。 大多数人的出发点 实验是一种新的结合分析，允许详细的研究 激动剂与高亲和力和低亲和力状态的相互作用 (KH，KL）的M1受体的性质，并测量M1受体的性质。 正常哺乳动物神经细胞M1受体机制 膜。 很明显，对于不同的KL/KH比率， 激动剂与生物化学活性密切相关， 相同的激动剂促进膜内 磷脂酰肌醇（PI）及其生理活性 兴奋皮质细胞的激动剂。 这些测量结果表明， 用于AD的Rx测试的五种激动剂中没有一种是良好的M1 激动剂 计划进行三个系列的实验，基于 大量的初步数据。 激动剂的研究将采用家兔 海马、脑干和颌下腺膜， M1、M2 h（心脏型）和M2 g（腺体型）受体， 分别 KL/KH和PI击穿的测量将 定义良好的M1激动剂的结构，并允许选择 具有高M1效力和M1/M2选择性的新型激动剂。 进一步的研究探索了主要结合位点的性质 和双功能激动剂的假定二级结合位点。 兔海马M1受体机制的研究 膜将检验我们的假设，即M1受体 成对工作，显示哪种过渡金属离子最好支持 KH状态，证明了变构剂是否可以改善 M1激动剂的结合或功效，并显示A1+， 生长抑素等直接干扰M1机制。 的 M1机制与体内干预的状态将是 在大鼠大脑中进行评估。 慢性去神经支配和 受体阻断将显示该机制如何响应 长期不活动。 输注研究 四氢氨基吖啶和M2激动剂氧震颤素将 显示是否扭曲了有益的反应。 最后 M1激动剂AF 102 B的替代治疗将 检查对正常和胆碱能的慢性影响- 失神经受体

The objective of the proposed work is to provide a rational scientific basis for cholinergic replacement therapy for memory disorders, specifically Alzheimer's disease (AD). This objective is based upon two closely related themes. The first is that the M1 muscarine receptor mechanism is worthy of intense study in its own right, because M1 receptors are primarily localized in the forebrain, appear essential for normal cerebral excitation and short-term memory, and have not been well studied. The second is that cholinergic therapy with M1 agonists is one of the best hopes for treating AD. The starting point for most of the experiments is a new binding assay which permits detailed studies of the interaction of agonists with the high and low affinity states (KH, KL) of M1 receptors, and measurements of the nature of the M1 receptor mechanism in normal, mammalian nerve cell membranes. It is clear that the KL/KH ratio for different agonists correlates closely with the biochemical activity of the same agonists in promoting the breakdown of intramembranous phosphoinositides (PI) and the physiological activity of these agonists in exciting cortical cells. These measurements show that none of the five agonists yet tested for the Rx of AD is a good M1 agonist. Three series of experiments are planned, based on extensive preliminary data. Studies of agonists will be with rabbit hippocampal, brainstem and submaxillary gland membranes for M1, M2h (heart type) and M2g (gland type) receptors, respectively. Measurements of KL/KH and PI breakdown will define the structure of good M1 agonists, and permit the selection of new agonists with high M1 efficacy and M1/M2 selectivity. Additional studies probe the nature of the primary binding site and hypothetical secondary binding sites for bifunctional agonists. Studies of the M1 receptor mechanism in rabbit hippocampal membranes will test our working hypothesis that M1 receptors work in pairs, show which transition metal ion(s) best support(s) the KH state, demonstrate whether allosteric agents can improve the binding or efficacy of M1 agonists, and show whether A1+++, somatostatin etc. directly interfere with the M1 mechanism. The status of the M1 mechanism with interventions in vivo will be assessed in rat brains. Studies of chronic denervation and receptor blockage will show how the mechanism responds to prolonged inactivity. Studies with infused tetrahydroaminoacridine and the M2 agonist, oxotremorine, will show whether either distorts beneficial responses. Finally replacement therapy with the M1 agonist AF102B will be examined for chronic effects on normal and cholinergically- denervated receptors.