Efferent Control of Hair Cell and Afferent Responses in the Semicircular Canals
Efferent Control of Hair Cell and Afferent Responses in the Semicircular Canals
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DOI：
10.1152/jn.91367.2008
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发表时间：
2009-09-01
影响因子：
2.5
通讯作者：
Highstein, Stephen M.
中科院分区：
文献类型：
--
作者：
Boyle, Richard;Rabbitt, Richard D.;Highstein, Stephen M.
博伊尔 R、兔子 RD、海斯坦 SM。毛细胞的传出控制和半规管的传入反应。 《神经生理学杂志》102：1513-1525，2009 年。首次发表于 2009 年 7 月 1 日； doi：10.1152/jn.91367.2008。内耳产生的声音和运动的感觉由大脑通过脑干内广泛的向心神经支配来控制。在半规管中，脑干传出神经元与机械感觉毛细胞和传入神经元的树突进行突触接触。在这里，我们检查传出作用对毛细胞和传入神经的相对贡献。实验是在牡蛎蟾蜍 Opsanus tau 身上进行的。传出系统通过脑干的电脉冲激活，并且通过同时记录传入神经的电压和来自毛细胞的细胞内电流和/或电压钳记录来量化对运动刺激的感觉反应。结果显示，传入细胞和毛细胞的突触输入导致相对较长延迟的细胞内信号传导反应：传入细胞兴奋，毛细胞抑制。一般来说，传出作用的净效应是传入背景放电的增加和角运动刺激增益的同时减少。毛细胞的抑制可能是配体门控打开主要基底外侧电导的结果。传出诱发电流的反转电位略低于毛细胞静息电位，从而导致小的超极化。起始潜伏期平均约为 90 毫秒，峰值响应潜伏期为 150-400 毫秒。毛细胞抑制通常比传入兴奋更持久，并且在某些情况下，在刺激停止后将毛细胞锁定在“关闭”状态>1秒。这些特征赋予动物强大的手段来调整运动感觉的灵敏度和动态范围。
Boyle R, Rabbitt RD, Highstein SM. Efferent control of hair cell and afferent responses in the semicircular canals. J Neurophysiol 102: 1513-1525, 2009. First published July 1, 2009; doi:10.1152/jn.91367.2008. The sensations of sound and motion generated by the inner ear are controlled by the brain through extensive centripetal innervation originating within the brain stem. In the semicircular canals, brain stem efferent neurons make synaptic contacts with mechanosensory hair cells and with the dendrites of afferent neurons. Here, we examine the relative contributions of efferent action on hair cells and afferents. Experiments were performed in vivo in the oyster toadfish, Opsanus tau. The efferent system was activated via electrical pulses to the brain stem and sensory responses to motion stimuli were quantified by simultaneous voltage recording from afferents and intracellular current- and/or voltage-clamp recordings from hair cells. Results showed synaptic inputs to both afferents and hair cells leading to relatively long-latency intracellular signaling responses: excitatory in afferents and inhibitory in hair cells. Generally, the net effect of efferent action was an increase in afferent background discharge and a simultaneous decrease in gain to angular motion stimuli. Inhibition of hair cells was likely the result of a ligand-gated opening of a major basolateral conductance. The reversal potential of the efferent-evoked current was just below the hair cell resting potential, thus resulting in a small hyperpolarization. The onset latency averaged about 90 ms and latency to peak response was 150-400 ms. Hair cell inhibition often outlasted afferent excitation and, in some cases, latched hair cells in the "off" condition for >1 s following cessation of stimulus. These features endow the animal with a powerful means to adjust the sensitivity and dynamic range of motion sensation.