Glowatzki Elisabeth, Fuchs Paul A
The Center for Hearing and Balance, Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2195, USA.
Nat Neurosci. 2002 Feb;5(2):147-54. doi: 10.1038/nn796.
Neurotransmitters are released continuously at ribbon synapses in the retina and cochlea. Notably, a single ribbon synapse of inner hair cells provides the entire input to each cochlear afferent fiber. We investigated hair cell transmitter release in the postnatal rat cochlea by recording excitatory postsynaptic currents (EPSCs) from afferent boutons directly abutting the ribbon synapse. EPSCs were carried by rapidly gating AMPA receptors. EPSCs were clustered in time, indicating the possibility of coordinate release. Amplitude distributions of spontaneous EPSCs were highly skewed, peaking at 0.4 nS and ranging up to 20 times larger. Hair cell depolarization increased EPSC frequency up to 150 Hz without altering the amplitude distribution. We propose that the ribbon synapse operates by multivesicular release, possibly to achieve high-frequency transmission.
神经递质在视网膜和耳蜗的带状突触处持续释放。值得注意的是，内毛细胞的单个带状突触为每根耳蜗传入纤维提供了全部输入。我们通过记录直接毗邻带状突触的传入终扣处的兴奋性突触后电流（EPSC），研究了新生大鼠耳蜗中毛细胞递质的释放。EPSC由快速门控的AMPA受体介导。EPSC在时间上呈簇状，表明存在协同释放的可能性。自发性EPSC的幅度分布高度不对称，峰值为0.4纳安，最大可达其20倍。毛细胞去极化使EPSC频率增加至150赫兹，而不改变幅度分布。我们认为带状突触通过多泡释放发挥作用，可能是为了实现高频传递。
