PHYSIOLOGICAL ROLE OF ACTIN IN SYNAPTIC TRANSMISSION

描述(摘自申请者的摘要)：突触是基本的 神经系统中信息处理和存储的单位。调制方式 突触强度被广泛认为是信息传递的机制 被编码在大脑中。为了了解突触的可塑性，专门的 作为神经传递基础的囊泡分泌物的形式必须首先 明白了。目前的研究使用了一种分离的实验制剂 七鳃鳗脊髓的体外培养。这种准备工作允许无与伦比地访问 用于显微注射的单一突触前元件和记录来自 从这种元件接受单突触输入的神经元。在注射时 在各种活性化合物中，这些注射的效果可以被监测 作为神经递质分泌的变化和突触的变化 超微结构。初步结果表明，突触小泡的内吞作用 似乎高度依赖F-肌动蛋白，而F-肌动蛋白可能作为一种 突触小泡返回到随后的小泡簇的支架 内吞作用。 拟议的研究将涉及注射各种肌动蛋白修饰剂。 直接进入活突触的突触前元素，并测量 这种注射对神经递质释放和突触的影响 超微结构。发生的形态变化的类型 这些注射将使我们能够估计突触小泡周期的位置。 试剂正在发挥作用。F-肌动蛋白结合、破坏和封端 特工将被注射。此外，实验将试图确定一种 主要肌动蛋白结合蛋白家族(肌球蛋白)，最近定位于神经 末端，在囊泡的胞吐或内吞中起作用。这些研究 将涉及克隆肌球蛋白II和V的七鳃鳗同系物，生产 干扰肌球蛋白/肌动蛋白相互作用的特异性抗体和注射 这些抗体进入突触前区域。这样的注射在 将对突触的超微结构和生理学进行评估。

DESCRIPTION(Adapted from applicant's abstract): The synapse is the elemental unit of information processing and storage in the nervous system. Modulation of synaptic strength is widely believed to be the mechanism by which information is encoded in the brain. To understand synaptic plasticity, the specialized form of vesicle secretion that underlies neurotransmission must first be understood. The present studies use an experimental preparation of an isolated lamprey spinal cord in vitro. This preparation allows unparalleled access to a single pre-synaptic element for microinjection and the ability to record from neurons which receive monosynaptic inputs from such an element. Upon injection of various active compounds, the effects of these injections can be monitored as changes in the secretion of neurotransmitter and by alterations in synapse ultrastructure. Preliminary results indicate that synaptic vesicle endocytosis appears to be highly dependent on F-actin and that F-actin may serve as a scaffold by which synaptic vesicles return to the vesicle cluster following endocytosis. The studies proposed will involve injecting a variety of actin modifying agents directly into the pre-synaptic element of a living synapse and measuring the effects such injections have on neurotransmitter release and synaptic ultrastructure. The type of morphological alterations that occur in response to these injections will enable estimation of where in the synaptic vesicle cycle the reagent is having an effect. F-actin binding, disrupting, and capping agents will be injected. In addition, experiments will seek to determine if a major actin binding protein family (myosins), recently localized to nerve terminals, have actions in vesicle exocytosis or endocytosis. These studies will involve cloning lamprey homologues of myosin II and V, production of specific antibodies that disrupt myosin/actin interactions and injections of these antibodies into pre-synaptic regions. The effect such injections have in synapse ultrastructure and physiology will be assessed.