CELLULAR MECHANISMS OF THE VESTIBULAR SYSTEM

前庭系统的细胞机制

• 批准号: 6379324
• 负责人: JAY M GOLDBERG
• 金额: $ 40.26万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-01 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6379324
• 关键词: Chelonia; acetylcholine; action potentials; adenosine; adenosine triphosphate; afferent nerve; calcitonin gene related peptide; ear hair cell; gamma aminobutyrate; glutamates; neural transmission; neuronal transport; neuropharmacology; potassium channel; potassium ion; synapses; vestibular nerve; voltage /patch clamp

The long-term goal of this work is to understand how vestibular organs work. The proper function of these organs is crucial to a healthy existence; damage can lead to debilitating vertigo, dizziness and inability to maintain study gaze. Mamammal, birds and reptiles have similar vestibular organs, with two classes of sensory receptor cell, the type I and type II hair cells. These cells transduce head movements into electrochemical signals that are transmitted across synapses to the terminals of afferent nerve fibers, which convey the signals to the brain in the form of electrical discharges. Efferent nerve fibers from the brain make synapses on h air cells and afferent nerve terminals, through which they influence afferent signals by unknown mechanisms. The specific aims are to characterize: 1) afferent synaptic transmission from the hair cells to the neurons; 2) the cellular mechanisms responsible for discharge regularity and maximum evoked discharge rates of afferent neurons; 3) efferent actions. In vitro preparations of the posterior semicircular canal organ of the turtle will be used. This organ lends itself to comparison of type I and type II hair cells, shows richly diverse efferent actions on afferent nerve fiber discharges, and is robust in vitro. Depending on the specific experiment, stimuli will be mechanical (displacement of the canal fluid), manipulations of membrane voltage or current in hair cells or afferent neurons, or electrical stimulation of efferent nerve fibers. The membrane voltage or current responses of hair cells and afferent neurons to these stimuli will be recorded intra cellularly with sharp micropipettes or patch pipettes. Both conventional (vesicular, orthograde) and unusual forms of transmission between the type I hair cell and afferent neuron will be characterized. Whether afferent discharge regularity is due to presynaptic (hair cell) or postsynaptic (afferent neuron) mechanisms will be tested. whether stages following mechanoelectrical traduction determine saturation of afferent discharge rates will be investigated. Efferent-evoked synaptic potentials and the neurotransmitter receptors responsible will be characterized.

这项工作的长期目标是了解前庭如何 器官工作。 这些器官的正常功能对于一个人的健康至关重要 健康存在；损伤会导致衰弱性眩晕， 头晕并且无法保持学习的目光。 哺乳动物、鸟类 和爬行动物有相似的前庭器官，有两类： 感觉受体细胞，I 型和 II 型毛细胞。 这些细胞 将头部运动转换成电化学信号 穿过突触传递至传入神经末梢 纤维，以以下形式将信号传递到大脑 放电。 来自大脑的传出神经纤维 h 空气细胞和传入神经末梢上的突触，通过 它们通过未知的机制影响传入信号。 具体目标是表征：1）传入突触 从毛细胞到神经元的传输； 2）蜂窝 负责排放规律性和最大排放量的机制 传入神经元诱发放电率； 3）传出动作。 在 后半规管器官的体外制备 将使用乌龟。 该器官适合与 I 型器官进行比较 和 II 型毛细胞，显示出丰富多样的传出作用 传入神经纤维放电，并且在体外具有鲁棒性。 取决于 在具体的实验中，刺激将是机械的 （管液的置换），膜的操作 毛细胞或传入神经元中的电压或电流，或电 刺激传出神经纤维。 膜电压或 毛细胞和传入神经元对这些的当前反应 刺激将用锋利的微量移液器记录在细胞内 或贴片移液器。 常规（囊状、顺行）和 I 型毛细胞和 I 型毛细胞之间不寻常的传播形式 将表征传入神经元。 是否有传入放电 规律性是由于突触前（毛细胞）或突触后（传入神经） 神经元）机制将受到测试。 是否有以下阶段 机电传导决定传入的饱和度 排放率将受到调查。 传出诱发突触 电位和负责的神经递质受体将是 特点。