RECOVERY OF DAMAGE TO THE VESTIBULAR-AUDITORY SYSTEM

单侧迷路切除术（UL）后的部分功能恢复，称为“前庭代偿”，已被用作中枢神经系统可塑性亚细胞研究的模型。以往的代偿研究已经“针对”特定的基因进行研究，使用免疫组织化学和杂交组织化学探针。我们建议使用“差异显示”（DD-PCR）技术来筛选从兔大脑前庭和听觉相关区域分离的基因产物，而不是针对特定的基因。与“目标基因”方法不同，DD-PCR筛选所有差异转录的基因产物。首先，我们将筛查斯卡帕神经节、前庭内侧核、结节和下丘。由于初级前庭-听觉传入投射到结节和DCN是单侧的，因此UL一侧的结构将接收到减少的初级传入输入，而完好一侧的结构将接收到正常输入。其次，我们将利用DD-PCR鉴定的寡核苷酸探针揭示不同mrna在接受UL的动物的组织分布和组织分布变化的时间过程。第三，有希望的分子将在更多的生理条件下进行研究。维持静态倾斜将用于提供不对称前庭刺激。单侧切除听骨链将产生不对称的声刺激。水平光动力刺激将用于向结节提供不对称的视觉攀爬纤维输入。光动力学输入将允许我们筛选在同一结构中差异表达的分子，结节，在刺激条件下介导两种不同的传入途径。第四，在蛋白质水平的类似筛选实验中，我们将使用二维电泳来筛选UL后差异表达的蛋白质。第五，一些分子可能仅仅通过改变其在细胞内的分布而不是通过改变表达来参与补偿或可塑性。我们将使用生理、免疫组织化学和超微结构相结合的方法，在“活化”的浦肯野细胞中检测PKC-delta分子。这些实验发现的基因产物可能在前庭和听觉适应中发挥作用，并为运动病和耳鸣等中枢神经疾病的药物治疗提供重要线索。

Partial recovery of function following a unilateral labyrinthectomy (UL), termed "vestibular compensation," has served as a model for investigations of subcellular investigations of central nervous system plasticity. Previous studies of compensation have "targeted" particular genes for study, using immunohistochemical and hybridization histochemical probes. Rather than target a particular genes, we propose to use the technique of "differential display" (DD-PCR) to screen gene products isolated from vestibular-and auditory-related regions the rabbit brain. Unlike the "targeted gene" approach, DD-PCR screens all differentially transcribed gene products. First, we will screen Scarpa's ganglion, medial vestibular nucleus, nodulus and inferior colliculus following UL. Since the primary vestibular-auditory afferent projects to the nodules and the DCN are unilateral, the structures on the side of the UL will receive a decreased primary afferent input and those on the intact side will receive a normal input. Second, we will use oligonucleotide probes identified by DD-PCR to reveal the tissue distribution and the time course of changes in tissue distribution of different mRNAs in animals that have received a UL. Third, promising molecules will be studied under more physiological conditions. Maintained static tilt will be used to provide asymmetric vestibular stimulation. Unilateral removal of the ossicular chain will be used to create asymmetric acoustic stimulation. Horizontal optokinetic stimulation will be used to provide asymmetric visual climbing fiber inputs to the nodulus. The optokinetic inputs will allow us to screen molecules that are differential expressed in the same structure, the nodulus, under stimulus conditions mediate db two different afferent pathways. Fourth, in analogous screening experiment at the protein level we will use two-dimensional electrophoresis to screen for proteins that are differential expressed following UL. Fifth, some molecules may participate in compensation or plasticity merely by changing their distribution within a cell rather than by changing expression. We will examine such a molecule, PKC-delta, in "activated" Purkinje cells using combined physiological, immunohistochemical and ultrastructural methods. Gene products uncovered by these experiments might play a role in both vestibular and auditory adaptation and provide important clues for the pharmacological treatment of central neural disorders such as motion sickness and tinnitus.