DEVELOPMENT OF EFFERENT NERVE FIBERS IN THE COCHLEA

描述(改编自申请者摘要)长期目标 该项目的主要内容是形态鉴定和生化鉴定 传出神经内的多样性和 与成人相比，发育中的相关突触连接， 老鼠的耳蜗虫。P.I.提议研究复杂的突触 内侧GABA能和胆碱能传出纤维的联系 螺旋束。研究目标旨在回答两个主要问题1) 是私家侦探在 老鼠的发育是一个短暂的发育事件，还是它也存在， 但之前没有注意到，在成年耳蜗里？2)突触阵列 仅由GABA能纤维形成的复合突触，还是这些 其他传出子系统也使用的模式？为了回答这些问题 问题，P.I.提出了以下项目：1)超结构 使用常规电子显微镜对突触进行研究 成年小鼠耳蜗内传出纤维的连通性。这项研究将 说明：a)连接模式：私家侦探将识别 不同的突触连接(其中14个在 发育中的小鼠)形成在传出和传入之间，以及在传出和传入之间 传入神经元本身；b)突触的类型：私家侦探将尝试 检测Corti成体器官是否使用复合突触 发育中的(高达1个PN)小鼠，即三元、连续和收敛 到目前为止，在培养中只在Corti器官中发现了突触；c) 内毛细胞和传入细胞所使用的突触附件 以及到达远处目标的传出终端。2. 免疫细胞化学/超微结构研究GABA能和 成熟和成体耳蜗胆碱能传出纤维可能 参与内毛细胞较低水平的复合型突触 感受器极点也将被引导。此外，私家侦探计划 形态和免疫化学特征的超微结构鉴定 在内螺旋束中表达GAP-43的囊状末端中， 只有在成人中含有这种生长蛋白的神经元通路 耳蜗骨。

DESCRIPTION (Adapted from Applicant's Abstract) The long-term objectives of the project are the identification of morphological and biochemical diversity within the efferent innervation and the patterns of the associated synaptic connectivity in the developing, as compared to adult, mouse cochlea. The P.I. proposes to study the complex synaptic connectivity of the GABAergic and cholinergic efferent fibers of the inner spiral bundle. The research goals aim to answer two principle questions 1) Is the CNS type of synaptic connectivity the P.I. has described in the developing mouse a transitory developmental event, or is it also present, but not noticed before, in the adult cochlea? 2) Are the synaptic arrays of compound synapses formed only by GABAergic fibers, or are these patterns also used by other efferent subsystems? In order to answer these questions, the P.I. proposes the following projects: 1) Ultrastructural studies, using conventional electron microscopy, of the synaptic connectivity of efferent fibers in the adult mouse cochlea. The study will elucidate: a) The patterns of connectivity: The P.I. will identify different synaptic connections (14 of which were demonstrated in the developing mouse) formed between the efferents and afferents, and between the afferents themselves; b) The types of synapses: The P.I. will try to detect if the adult organ of Corti uses compound synapses as discovered in the developing (up to 1 PN) mouse, i.e., triadic, serial and converging synapses so far identified only in the organ of Corti in culture; c) The synaptic appendages used by the inner hair cells and by both the afferent and efferent terminals in reaching distant targets. 2 Immunocytochemical/ultrastructural studies to investigate GABAergic and cholinergic efferent fibers in the maturing and adult cochlea that may partake in compound synapses at the lower level of the inner hair cell receptor poles will also be conducted. Additionally, the P.I. plans to identify ultrastructurally the morphological and immunochemical character of vesiculated endings that express GAP-43 in the inner spiral bundle, the only neuronal pathway that contains this growth protein in the adult cochlea.