DEVELOPMENT OF EFFERENT NERVE FIBERS IN THE COCHLEA

本研究的长期目标是确定 与分化传出神经的免疫细胞化学特征 在光镜和电镜水平上观察到小鼠的神经系统。的 培养中的分离的Corti器官将用作最终对照， 辨别螺旋神经节细胞局部提供的神经支配 从中央起源。特别重要的是研究 传出样囊泡末梢及其带状传入/传出 与Corti器内毛细胞的相互突触， 培养和完整动物中，以确定其当地来源， 免疫细胞化学特征当前的目标是确定 传出神经支配内的多样性，并确定 不同亚基的发育顺序。我们特别 目的：1）研究神经丝的发育模式 完整动物中的免疫反应性（标记所有神经元元件） 并在培养中作为解释个体免疫细胞化学 耳蜗神经支配模式; 2）研究CGRP在耳蜗中的表达， 毛细胞的神经支配及其随后从外部消失 毛细胞区的免疫细胞化学研究 显微镜下观察到神经活性物质AChE、ChAT、GAD/GABA、CGRP和 脑啡肽，以确定其分化的顺序， 推测共定位; 4）研究超微结构的身份， 内螺旋束中保留GAP-43的独特的新途径 （生长相关蛋白-43）活性。 建议的研究最重要的方面是，首先，辨别 与内毛细胞相关的感觉神经传出特化 推测为耳蜗起源;第二，确定超微结构 和传出神经支配的发展顺序，最后， 区分过渡性发展模式及其 在成熟的动物中的对应物。我们希望这些研究将 超越物种界限，帮助我们更好地理解我们自己的听觉 系统

The long-term objectives of the research are to define the morphological versus immunocytochemical characteristics of the differentiating efferent system in the mouse at the light and electron microscope levels. The isolated organ of Corti in culture will be used as an ultimate control in discerning the innervation provided locally by the spiral ganglion cells from that of central origin. Of special importance will be the study of efferent-like vesiculated endings and their ribbon-afferent/efferent reciprocal synapses with the inner hair cells in the organ of Corti in culture and in the intact animal to determine their local source and immunocytochemical character. The immediate goal is to identify the diversity within the efferent innervation and to determine the developmental sequence of the different subunits. Specifically, we propose: l) to study the detailed developmental pattern of neurofilament immunoreactivity (which labels all neuronal elements) in the intact animal and in culture as a guide for interpreting individual immunocytochemical patterns of cochlear innervation; 2) to study CGRP expression in the innervation of the hair cells and its subsequent extinction from the outer hair cell region; 3) to study immunocytochemically at the electron microscope level the neuroactive substances AChE, ChAT, GAD/GABA, CGRP and enkephalins to determine the sequence of their differentiation and presumptive colocalization; 4) to study the ultrastructural identity of the distinct, new pathway in the inner spiral bundle which retains GAP-43 (growth-associated protein-43) activity in the adult mouse. The most important aspects of the proposed study are first, to discern the neurosensory efferent specializations associated with the inner hair cells presumed to be of cochlear origin; second, to define the ultrastructure and developmental sequence of efferent innervation, and lastly to distinguish between the transitory developmental patterns and their counterparts in the maturing animal. We hope that these studies will transcend species-lines and help us to better understand our own auditory system.