Moser Tobias, Brandt Andreas, Lysakowski Anna
Department of Otolaryngology and Center for Molecular Physiology of the Brain, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
Cell Tissue Res. 2006 Nov;326(2):347-59. doi: 10.1007/s00441-006-0276-3. Epub 2006 Aug 31.
Hearing and balance rely on the faithful synaptic coding of mechanical input by the auditory and vestibular hair cells of the inner ear. Mechanical deflection of their stereocilia causes the opening of mechanosensitive channels, resulting in hair cell depolarization, which controls the release of glutamate at ribbon-type synapses. Hair cells have a compact shape with strong polarity. Mechanoelectrical transduction and active membrane turnover associated with stereociliar renewal dominate the apical compartment. Transmitter release occurs at several active zones along the basolateral membrane. The astonishing capability of the hair cell ribbon synapse for temporally precise and reliable sensory coding has been the subject of intense investigation over the past few years. This research has been facilitated by the excellent experimental accessibility of the hair cell. For the same reason, the hair cell serves as an important model for studying presynaptic Ca(2+) signaling and stimulus-secretion coupling. In addition to common principles, hair cell synapses differ in their anatomical and functional properties among species, among the auditory and vestibular organs, and among hair cell positions within the organ. Here, we briefly review synaptic morphology and connectivity and then focus on stimulus-secretion coupling at hair cell synapses.
听觉和平衡依赖于内耳听觉和前庭毛细胞对机械输入的精确突触编码。其静纤毛的机械偏转导致机械敏感通道开放，引起毛细胞去极化，进而控制带状突触处谷氨酸的释放。毛细胞形状紧凑，极性很强。与静纤毛更新相关的机械电转导和活跃的膜周转主要发生在顶端区域。递质释放发生在基底外侧膜沿线的多个活性区。在过去几年中，毛细胞带状突触在时间上精确且可靠地进行感觉编码的惊人能力一直是深入研究的主题。毛细胞出色的实验可及性推动了这项研究。出于同样的原因，毛细胞是研究突触前Ca(2+)信号传导和刺激-分泌偶联的重要模型。除了共同的原理外，毛细胞突触在物种之间、听觉和前庭器官之间以及器官内毛细胞的位置之间，在解剖学和功能特性上存在差异。在这里，我们简要回顾突触形态和连接性，然后重点关注毛细胞突触处的刺激-分泌偶联。
