MOLECULAR CHARACTERIZATION OF MUSCARINIC ACH RECEPTORS

提出了一种为期5年的分子水平的战略来攻击一个 脊椎动物神经发育的重要问题：“中枢神经系统如何 神经元为适当的信号创造专门的突触后区 转导？“大脑的基本活动是发出信号 细胞之间--潜在的发育、维持机制 和信号转导的可塑性是 大脑功能。 M胆碱型乙酰胆碱受体被选为原型 用于研究中枢神经系统突触后特化。这些受体是 牵涉到一系列生理和行为过程中， 包括有意识的唤醒、学习和记忆。此外， 因为阿尔茨海默氏症与ACh的死亡有关- 含有细胞的突触后胆碱能细胞的新研究 可能与公众健康有相当大的相关性。 拟议的工作追求的是三个基本问题 重大发现：(1)中枢神经系统(但不是心脏)表达 新的86 kDa“胚胎型”MAChR，在轴突期间丰富 增长，在发展中下调，并被 一个72 kDa的“成人型”分子；(2)在体内，神经元严格 调节受体的位置，所有分子都定位 到树突，甚至在突触形成之前；(3)发育 神经元在受体的位置和位置上是“可塑性的” 86K/72K分子类型的表达。这些新的和重要的 在对鸡中枢神经系统的研究中进行了观察，鸡中枢神经系统是一种广泛使用的 脊椎动物神经发育的模型。有三个具体目标 被选为扩展这些发现的最关键的因素： (1)确定86 kDa和72 kDa的起源和结构 通过鉴定鸡的受体基因和受体分子 它们在发育中的中枢神经系统中的转录。 (2)确定86K和72K分子的局域化位置 与突触连接相关，评估可能的机制 潜在的位置和可塑性。 (3)比较86K和72K受体的功能，探讨 神经突起时期可能的新的生长相关作用 树枝形成和突触发生。

A 5-year molecular-level strategy is proposed for attacking an important problem in vertebrate neurodevelopment: "How do CNS neurons create postsynaptic zones specialized for proper signal transduction?" The elementary activity of the brain is signaling between cells -- mechanisms underlying development, maintenance and plasticity of signal transduction are at the foundation of brain function. Muscarinic acetylcholine receptors have been selected as prototypes for studying CNS postsynaptic specialization. These receptors are implicated in a host of physiological and behavioral processes, including conscious arousal, learning and memory. Moreover, because Alzheimer's disease is associated with the death of ACh- containing cells, new studies of cholinoceptive postsynaptic cells could have considerable relevance to the public health. The proposed work pursues fundamental questions stimulated by three significant discoveries: (1) The CNS (but not heart) expresses a novel 86 kDa "embryonic" type MAChR, abundant during neurite growth, that developmentally down-regulates and is supplanted by a 72 kDa "adult type" molecules; (2) In vivo, neurons stringently regulate the placement of receptors, with all molecules localized to dendrites even before synapses have formed; (3) Developing neurons are "plastic" with respect to receptor placement and expression of 86K/72K molecular types. These new and important observations were made in studies of the chicken CNS, a widely-used model for vertebrate neurodevelopment. Three specific aims have been selected as most critical for expanding these findings: (1) To establish the origin and structure of the 86 kDa and 72 kDa receptor molecules by characterizing chicken receptor genes and their transcription in the developing CNS. (2) To determine where the 86K and 72K molecules are localized relative to synaptic junctions, assessing possible mechanisms underlying placement and plasticity. (3) To compare the function of 86K and 72K receptors, investigating possible novel growth-associated roles during the period of neurite arborization and synaptogenesis.