CELLULAR MECHANISMS OF THE VESTIBULAR SYSTEM

这项工作的长期目标是了解前庭是如何 器官工作。 这些器官的正常功能对一个 健康的存在;损害可导致衰弱性眩晕， 头晕和无法保持研究凝视。 哺乳动物、鸟类 爬行动物也有类似的前庭器官， 感觉感受器细胞，I型和II型毛细胞。 这些细胞 电化学信号， 通过突触传递到传入神经末梢 神经纤维，它将信号以 放电 大脑的传出神经纤维 h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。 具体的目的是表征：1）传入突触 从毛细胞到神经元的传递; 2）细胞 负责放电规律性和最大化的机制 传入神经元的诱发放电率; 3）传出活动。 在 后半规管器的体外制备 海龟将被使用。 这个器官适合于比较I型 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，并且在体外是稳健的。 取决 在具体实验中，刺激将是机械的 （根管液体移位），膜操作 毛细胞或传入神经元中的电压或电流，或电 传出神经纤维的刺激。 膜电压或 毛细胞和传入神经元对这些信号的电流反应 用尖锐的微量移液管在细胞内记录刺激 或贴片移液管。 常规（囊状，顺行）和 I型毛细胞和 将表征传入神经元。 传入放电是否 规律性是由于突触前（毛细胞）或突触后（传入 神经元）机制进行测试。 是否有以下阶段 机械电传导决定传入神经的饱和度 将调查排放率。 传出诱发突触 电位和负责的神经递质受体将 表征了

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.