RECOVERY OF DAMAGE TO THE VESTIBULAR-AUDITORY SYSTEM

单侧迷路切除(UL)后功能的部分恢复，被称为前庭代偿，已成为研究中枢神经系统可塑性的亚细胞研究的模型。以前关于补偿的研究使用免疫组织化学和杂交组织化学探针来“瞄准”特定的基因进行研究。我们不是针对某个特定的基因，而是使用“差异显示”(DD-PCR)技术来筛选从兔脑前庭和听觉相关区域分离出来的基因产物。与“靶向基因”方法不同，DD-PCR筛选所有差异转录的基因产物。首先，我们将对UL后的Scarpa神经节、前庭内侧核、小结和下丘进行筛查。由于前庭-听觉对结节和DCN的初级传入投射是单侧的，UL侧的初级传入投射将减少，而完好侧的初级传入投射将得到正常的投射。其次，我们将使用DD-PCR鉴定的寡核苷酸探针来揭示不同mRNAs在接受UL的动物体内的组织分布和组织分布变化的时间进程。第三，有希望的分子将在更多的生理条件下进行研究。保持静态倾斜将用于提供不对称的前庭刺激。单侧切除听骨链将用于产生不对称的声刺激。水平视动刺激将被用来为结节提供不对称的视觉攀升纤维输入。光动力输入将允许我们筛选在相同结构中差异表达的分子，在刺激条件下，结节介导两种不同的传入途径。第四，在蛋白质水平的相似筛选实验中，我们将使用双向电泳法来筛选UL后差异表达的蛋白质。第五，一些分子可能仅仅通过改变它们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。我们将使用生理学、免疫组织化学和超微结构相结合的方法，在“激活的”浦肯野细胞中检测这种分子，PKC-Delta。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，并为中枢神经疾病(如运动病和耳鸣)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.