The Glycine Receptor in a Rat Tinnitus Model: A Possible Therapeutic Target

描述（由申请人提供）：慢性耳鸣是高达15%的人口经历的一种幻听觉。2%到10%的耳鸣人群通常会经历连续的高频铃声或嘶嘶声，声音足够大，严重影响他们的生活质量（库珀，1994年）。已经发现，耳鸣随着年龄的增长而增加。因此，耳鸣的发病率可能会增加，由于寿命的增加和娱乐性噪音暴露。耳鸣的病因有哪些？耳鸣的病因有哪些？一个与其他感觉系统的研究结果相似的工作假设表明，部分传入神经阻滞导致中枢变化，通常涉及抑制性神经传递的改变。部分外周听觉传入阻滞可引起耳鸣，与耳蜗背核（DCN）抑制性甘氨酸能功能的选择性丧失一致。拟议的研究将检查功能和分子神经化学的影响，老龄化的大鼠耳鸣的行为证据。初步结果发现年龄和噪声暴露相关的变化甘氨酸受体和神经营养因子神经化学在DCN的大鼠耳鸣的行为证据。拟议的研究将比较年轻和老年对照组之间的功能和分子神经化学变化，以及年轻和老年的声音暴露大鼠耳鸣的行为证据。具体而言：1）信息和蛋白质的定量测量将用于检查由甘氨酸受体、支架蛋白、桥蛋白和保护性神经营养因子BDNF组成的亚基的变化; 2）来自DCN梭形细胞的记录将与行为研究/间隙检测平行，并检查抑制反应特性和甘氨酸受体敏感性，以及3）定量受体结合将用于检查甘氨酸和神经营养因子受体药理学的变化。这些研究的结果将提供新的信息耳鸣相关的变化，甘氨酸神经传递和可能的神经营养保护耳鸣的动物模型。了解衰老对耳鸣相关的神经化学变化的影响，这些变化与甘氨酸和BDNF受体（TrkB）功能有关，这可能有助于确定开发和测试用于治疗耳鸣的新型选择性药物的独特靶点。

DESCRIPTION (provided by applicant): Chronic tinnitus is a phantom auditory sensation experienced by up to 15% of the population. Between 2 and 10% of the tinnitus population typically experience a continuous high frequency ringing or hiss sufficiently loud to impact severely on their quality of life (Cooper, 1994). Tinnitus has been found to increase with aging. Thus, the incidence of tinnitus is likely to increase due to increased longevity and recreational noise exposure. Much of the present thinking regarding the generation of tinnitus revolves around the appearance of spontaneous activity and neural hyperactivity in certain central auditory structures. A working hypothesis which parallels findings in other sensory systems suggests that partial deafferentation leads to central changes, generally involving altered inhibitory neurotransmission. Partial peripheral auditory deafferentation may produce tinnitus, coincident with a selective loss of inhibitory glycinergic function in the dorsal cochlear nucleus (DCN). Proposed studies will examine the functional and molecular neurochemical impact of aging in rats with behavioral evidence of tinnitus. Preliminary results find age and noise-exposure related changes in glycine receptor and neurotrophic factor neurochemistry in DCN of rats with behavioral evidence of tinnitus. Proposed studies will compare functional and molecular neurochemical changes between young and aged controls, and young and aged sound-exposed rats with behavioral evidence of tinnitus. Specifically: 1) quantitative measures of message and protein will be used to examine changes in the subunit make up of the glycine receptor, the scaffolding protein, gephyrin, and the protective neurotrophin BDNF; 2) recordings from DCN fusiform cells will parallel behavioral studies/gap detection and examine inhibitory response properties and glycine receptor sensitivity and 3) quantitative receptor binding will be used to examine changes in glycine and neurotrophin receptor pharmacology. Findings from these studies will provide new information regarding tinnitus-related changes in glycine neurotransmission and possible neurotrophin protection in an animal model of tinnitus. Understanding the impact of aging on tinnitus-related changes in neurochemistry related to glycine and the BDNF receptor (TrkB) function might help define unique targets for the development and testing of novel selective drugs for the treatment of tinnitus.