Development of Spiral Ganglion Neurons

这项MRI研究计划助学金为期一年，旨在获得有关内耳神经支配的试点数据。哺乳动物耳中的感觉感受器细胞有两种类型，内毛细胞(IHC)和数量更多的外毛细胞(OHC)。这些感受器细胞由神经细胞(神经元)支配，神经细胞(神经元)的细胞体位于耳朵螺旋神经节的结构中。成年动物有两种类型的螺旋神经节细胞，基于它们与一种或另一种毛细胞的接触，它们的纤维直径，以及它们细胞体的大小和形状。仍然令人费解的是，OHC大约占所有毛细胞的3/4，从不到所有神经节细胞的十分之一获得接触。目前尚不清楚神经元是如何发育成这两类的。在新生动物中，一些研究表明，这些细胞在形态上与成年神经元不同，最初是一个同质的群体。这项计划拨款是澄清新生啮齿动物中接触毛细胞的螺旋神经节神经元的解剖和超微结构的初步步骤。将使用光学显微镜和电子显微镜，结合单细胞的染料填充技术和特定的抗体染色。对这些数据的分析将为后来的全面提案提供基础，以追求这些神经元的发育。这个项目是关于一组对理解听力机制很重要的细胞。这些数据将提供必要的基线，以便能够准备一项关于这些细胞发展的完整研究项目。

This MRI Research Planning Grant is for one year to obtain pilot data on innervation f the inner ear. The sensory receptor cells in the cochlea of the mammalian ear are of two types, the inner hair cells (IHC) and the far more numerous outer hair cells (OHC). These receptor cells are innervated by nerve cells (neurons) that have their cell bodies in a structure called the spiral ganglion of the ear. Adult animals have two types of spiral ganglion cells, based on their contacts with one or the other type of hair cells, the diameter of their fibers, and size and shape of their cell bodies. It remains puzzling that the OHC, representing roughly 3/4 of all the hair cells, receive contacts from fewer than one-tenth of all the ganglion cells. It is not clear how the neurons develop into these two classes. In newborn animals, some studies suggest that these cells are morphologically different from the adult neurons, and are initially a homogeneous population. This planning grant is a preliminary step toward clarifying the anatomy and ultra- structure of the spiral ganglion neurons that contact OHCs in newborn rodents. Both light microscopy and electron microscopy will be used, in conjunction with dye-filling techniques for single cells, and specific antibody staining. The analysis of these data will provide a basis for a later full proposal to pursue the development of these neurons. This project is on a group of cells important in understanding mechanisms of hearing. The data will provide a needed baseline to allow preparation of a full research project on development of these cells.