CELLULAR MECHANISMS OF THE VESTIBULAR SYSTEM

我们的长期目标是了解细胞机制决定 前庭神经传入的放电特性。为此，一个 本实验建立了甲鱼后巩膜的体外制备方法。 其优点是：1)传入放电特性 在体外制剂和在完整的呼吸中没有区别 动物。2)I型毛细胞局限于中心区，它们 构成了这个区域的绝大多数毛细胞，它们是 由具有独特生理特性的传入神经支配的。在……里面 一条相似的静脉，但传入神经在生理上有所不同 属性支配外围区域的不同部分。因此，通过 研究从不同地区采集的毛细胞，应该是 可能将毛细胞和传入神经的生理学联系起来 让他们兴奋。3)电刺激传出产生 一些传入神经元兴奋，另一些传入神经元抑制。因为两个人 不同种类的传入神经支配神经上皮的不同部分， 对从特定区域提取的毛细胞的研究应该可以让我们 确定这两种传出活动的细胞基础。4)头发 来自这个器官的细胞相对容易分离和鉴定 全细胞密封式录音。 有三个具体目标：1)完成对前庭的研究- 体外制备中的神经放电。传入神经的特征是 就它们对头部旋转的反应而言，它们对 电刺激传出纤维，以及定位和 它们的外周末端的形态。2)描述类型I的特征 和II型毛细胞，分离自大脑的特定区域。 神经上皮细胞，就其电压和离子敏感电流而言， 以及由传出递质乙酰胆碱引起的电流 (ACH)。3)将研究范围扩大到甲鱼的椭圆形黄斑 因为这个末端器官为一些计划中的研究提供了有利条件 在接下来的几年。 拟议的研究意在对两个问题作出贡献。什么 是I型毛细胞及其花蕾的独特功能 结局呢？传出调节的作用是什么？ 前庭末梢器官？这些问题对理解这些问题很重要 前庭迷路在健康和疾病中的操作。

Our long-term goal is to understand the cellular mechanisms determining the discharge properties of vestibular-nerve afferents. To this end, an in vitro preparation of the turtle posterior crista has been developed. Its advantages are: 1) Afferent discharge properties are indistinguishable in the in vitro preparation and in intact, respiring animals. 2) Type I hair cells are restricted to a central zone, they make up the large majority of hair cells in this zone, and they are innervated by afferents having distinctive physiological properties. In a similar vein, bouton afferents differing in their physiological properties innervate distinct parts of the peripheral zone. Hence, by studying hair cells harvested from the different regions, it should be possible to correlate the physiology of hair cells and of the afferents innervating them. 3) Electrical stimulation of efferents produces excitation in some afferents and inhibition in others. Since the two kinds of afferents innervate distinct parts of the neuroepithelium, a study of hair cells drawn from specific regions should allow us to determine the cellular basis for both kinds of efferent actions. 4) Hair cells from this organ are relatively easy to isolate and to characterize with whole-cell tight-seal recordings. There are three specific aims: 1) To complete studies of vestibular- nerve discharge in the in vitro preparation. Afferents are characterized in terms of their responses to head rotations, their responses to electrical stimulation of efferent fibers, and the location and morphology of their peripheral terminations. 2) To characterize type I and type II hair cells, isolated from specific regions of the neuroepithelium, in terms of their voltage- and ion-sensitive currents, as well as the current evoked by the efferent transmitter, acetylcholine (ACh). 3) To extend the studies to the utricular macula of the turtle because this end organ offers advantages for some of the research planned for the next several years. The proposed studies are intended to contribute to two questions. What are the distinctive functions of type I hair cells and their calyx endings? What is the function of the efferent regulation of the vestibular end organs? The questions are of importance in understanding the operation of the vestibular labyrinth in health and disease.