DEVELOPMENT OF EFFERENT NERVE FIBERS IN THE COCHLEA

描述（改编自申请人的摘要）长期目标 的项目是形态和生化鉴定 传出神经支配的多样性和 与成人相比， 小鼠耳蜗私家侦探建议研究复杂的突触 内皮层GABA能和胆碱能传出纤维的连接 螺旋维管束研究目标旨在回答两个主要问题1） 中枢神经系统的突触连接是P.I.描述了在 发育中的小鼠是暂时的发育事件，还是也存在， 但之前没有注意到，在成年人的耳蜗里？2)是突触阵列 只由GABA能纤维形成的复合突触，或者这些 其他传出子系统也使用的模式？为了回答这些 问题私家侦探提出了以下几个方面的设想：1）超微结构 使用传统的电子显微镜对突触的研究， 成年小鼠耳蜗传出纤维的连接。这项研究将 阐明：a）连接模式：P.I.将确定 不同的突触连接（其中14个在 发育中的小鼠）之间形成的传出和传入，和之间 传入神经本身; B）突触的类型：P.I.将试图 检测成年人的Corti器官是否使用复合突触， 发育中的（至多1 PN）小鼠，即，三元、串联和收敛 到目前为止，只在培养的Corti器官中发现了突触; c） 由内毛细胞和传入纤维使用的突触附属物 和传出终末到达远处的目标。2 免疫细胞化学/超微结构研究以研究GABA能和 成熟和成年耳蜗中的胆碱能传出纤维， 参与内毛细胞下层的复合突触 还将进行接收极。此外，P.I.计划 超微结构鉴定形态学和免疫化学特征 在内螺旋束中表达GAP-43的囊泡状末端， 在成人中，只有神经元通路含有这种生长蛋白， 耳蜗

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.