MOLECULAR CHARACTERIZATION OF MUSCARINIC ACH RECEPTORS

提出了一个5年分子水平的战略， 脊椎动物神经发育中重要问题：“中枢神经系统如何 神经元产生突触后区专门用于适当的信号 转导？“大脑的基本活动是发出信号， 在细胞之间--发育、维持 和可塑性的信号转导是基础， 大脑功能 毒蕈碱型乙酰胆碱受体已被选为原型 用于研究中枢神经系统突触后特化。 这些受体是 与许多生理和行为过程有关， 包括有意识的唤醒、学习和记忆。 此外，委员会认为， 因为阿尔茨海默病与乙酰胆碱的死亡有关， 含细胞，胆碱能突触后细胞的新研究 可能与公众健康有很大关系。 拟议的工作追求的基本问题，激发了三个 重大发现：（1）中枢神经系统（但不是心脏）表达一种 新的86 kDa“胚胎”型MAChR，在神经突期间丰富 增长，发展下调，并取代 a 72 kDa“成人型”分子;（2）在体内，神经元严格地 调节受体的位置，所有分子都定位在 甚至在突触形成之前就已经形成了;（3）发育中的 神经元在受体位置方面是“可塑的”， 86 K/72 K分子类型的表达。 这些新的和重要的 在鸡中枢神经系统的研究中进行了观察， 脊椎动物神经发育的模型。 三个具体目标 被选为扩大这些发现的最关键因素： (1)为了确定86 kDa和72 kDa的来源和结构， 通过表征鸡受体基因和 它们在发育中的CNS中的转录。 (2)为了确定86 K和72 K分子的位置， 相对于突触连接，评估可能的机制 潜在的位置和可塑性。 (3)为了比较86 K和72 K受体的功能， 神经突时期可能的新的生长相关作用 树枝化和突触发生。

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.