A New Model for In Vivo Vestibular Pharmacology

描述(由申请人提供)：本申请代表了一项探索性和开发建议，旨在设计、测试和制造一种实验模型，在该模型中可以实现内耳迷路的急性灌流，以用于前庭药理学研究。这种新模型的主要优点是可以将药物操作直接引入迷路，同时记录初级传入神经元的放电，代表前庭感觉上皮细胞的输出。因此，可以直接确定操作对自发和刺激诱发放电的影响，从而使未来的研究能够解决当代药理学工具(例如受体激动剂和拮抗剂、电导特异性激动剂和拮抗剂等)所针对的各种问题。是适用的。两个假设将通过一套具体的目标进行测试，这些目标将全面测试该模型的有效性。将建造一个灌流液输送系统，以解决设计中针对外周前庭系统基本功能的关键技术问题。初步研究已经确定了传入放电中可能存在的伪影，可能是灌流液压力的突然变化造成的。灌流液输送系统将被专门设计和制造，以消除或减少这些人工制品。该系统的设计和制造将反映神经生物学和微流体工程之间的合作，使用微电子机械系统(MEMS)工程工具构建微流体设备(芯片)，以管理灌流液直接流向专门准备的龙猫内耳周围淋巴空间。将使用灌流液的测试电池，以解决特定溶液成分对毛细胞和投射在整个脊神经和椭圆形神经上皮细胞的传入神经元的可及性。这些实验有电生理和形态成分，通过传入放电记录和前庭毛细胞将这些溶液结合的直接成像，将提供测试溶液并监测效果。将进行的实验将检验第二个假设，即在传入神经元中存在跨膜AMPA受体调节蛋白(TARP)。这些实验在为药理操作准备的有效性提供详细的直接测试的同时，还将解决前庭传入中的Tarps的功能。这些结果有可能激发对外周前庭系统感觉处理的新的研究方向。 公共卫生相关性：根据这一探索性和发展计划进行的研究将产生一个哺乳动物模型系统，通过该系统可以直接测试药物对内耳前庭系统的影响以及传递到中枢神经系统的信号。这项调查的结果将导致未来的研究，改善我们对内耳内神经化学和药物相互作用的理解。该系统还可能为内耳疾病的新疗法提供试验台，并有助于开发新的疗法，帮助受损内耳组织的神经康复。

DESCRIPTION (provided by applicant): This application represents an exploratory and development proposal to design, test, and fabricate an experimental model in which acute perfusions of the inner ear labyrinth can be achieved for investigations of vestibular pharmacology. The principal advantage of this new model is that the pharmacologic manipulations can be introduced directly into the labyrinth while recording the discharge of primary afferent neurons, representing the output of vestibular sensory epithelia. Therefore, the effect of the manipulations on spontaneous and stimulus-evoked discharge can be directly determined, enabling future investigations addressing a wide variety of questions for which contemporary pharmacologic tools (e.g. receptor agonists and antagonists, conductance-specific agonists and antagonists, etc.) are applicable. Two hypotheses will be tested through a set of specific aims that will fully test the efficacy of the model. A perfusate delivery system will be constructed that addresses key technical issues, specific to the basic function of the peripheral vestibular system, in its design. Pilot studies have identified potential artifacts in afferent discharge that likely resulted from abrupt changes in perfusate pressure. The perfusate delivery system will be specifically designed and fabricated to eliminate or minimize these artifacts. The design and fabrication of this system will reflect a collaboration between neurobiology and microfluidics engineering, using tools of micro-electro- mechanical systems (MEMS) engineering to construct a microfluidics device (chip) to manage the flow of perfusate directly to the inner ear perilymphatic space of specially prepared chinchillas. A test battery of perfusate solutions will be utilized that address the accessibility of specific solution constituents to hair cells and afferent neurons projecting throughout the crista and utricular neuroepithelia. These experiments have electrophysiologic as well as morphologic components, whereby test solutions will be delivered and the effects monitored through afferent discharge recordings as well as from direct imaging of the incorporation of these solutions by vestibular hair cells. Experiments will be conducted that will test a second hypothesis regarding the presence of transmembrane AMPA-receptor regulatory proteins (TARPs) within the afferent neurons. While providing a detailed direct test of the efficacy of the preparation for pharmacologic manipulations, these experiments will also address the functionality of TARPs in vestibular afferents. These results have the potential to motivate a new line of investigation for sensory processing in the peripheral vestibular system. PUBLIC HEALTH RELEVANCE: The research to be conducted under this exploratory and development proposal will produce a mammalian model system through which direct testing of pharmaceutical agents can be conducted with respect to their influence on the inner ear vestibular system and the signals that are transmitted to the central nervous system. The results from this investigation will lead to future studies ameliorating our understanding of neurochemical and pharmacologic interactions within the inner ear. This system may also provide a test bed for new treatments of inner ear disorders, as well as contribute to the development of new therapies that will assist in neural rehabilitation of damaged inner ear tissues.