Popper A N, Saidel W M
Department of Zoology, University of Maryland, College Park 20742.
Hear Res. 1990 Jul;46(3):211-27. doi: 10.1016/0378-5955(90)90003-8.
Using transmission electron microscopy, we quantitatively analyzed the afferent and efferent synapses on 67 sensory hair cells along the saccular epithelium of the oscar (Astronotus ocellatus), a cichild fish with a non-specialized ear. The synaptic profile (number of afferent and efferent synapses per cell) varied considerably among cells. The number of synapses per hair cell ranged from three to 24, and all but six of the 67 hair cells had both afferent and efferent synapses. Statistical analysis showed that the synaptic profiles did not significantly vary anywhere on the saccular epithelium except at the edges. There, hair cells had significantly fewer efferent synapses than hair cells in other epithelial regions. This statistical variation in efferent synapse distribution in different epithelial regions corresponds with the lengths of ciliary bundles in these regions. The synapses on hair cells showed a regional specificity in position. In all cells synapses were never located more apically than the top of the nucleus. On hair cells towards the periphery, the most apical synapse on the hair cells tended to be afferent. On more centrally located cells, the most apical synapse was efferent in 92% of the cells.
我们使用透射电子显微镜，对奥斯卡鱼（眼斑星丽鱼）球囊上皮中的67个感觉毛细胞上的传入和传出突触进行了定量分析。奥斯卡鱼是一种具有非特化耳朵的丽鱼科鱼类。突触分布情况（每个细胞的传入和传出突触数量）在不同细胞间差异很大。每个毛细胞的突触数量从3个到24个不等，67个毛细胞中除了6个之外都同时具有传入和传出突触。统计分析表明，除了边缘区域外，球囊上皮其他部位的突触分布情况没有显著差异。在边缘区域，毛细胞的传出突触数量明显少于其他上皮区域的毛细胞。不同上皮区域传出突触分布的这种统计差异与这些区域纤毛束的长度相对应。毛细胞上的突触在位置上表现出区域特异性。在所有细胞中，突触从不位于比细胞核顶部更靠顶端的位置。在朝向周边的毛细胞上，毛细胞最顶端的突触往往是传入突触。在位置更靠中心的细胞上，92%的细胞中最顶端的突触是传出突触。
