PDF(Pubmed)
Abstract：
The global health concern posed by age-related visual impairment highlights the need for further research focused on the visual changes that occur during the process of aging. To date, multiple sensory alterations related to aging have been identified, including morphological and functional changes in inner hair cochlear cells, photoreceptors, and retinal ganglion cells. While some age-related morphological changes are known to occur in rod bipolar cells in the retina, their effects on these cells and on their connection to other cells via ribbon synapses remain elusive. To investigate the effects of aging on rod bipolar cells and their ribbon synapses, we compared synaptic calcium currents, calcium dynamics, and exocytosis in zebrafish (Danio rerio) that were middle-aged (MA,18 months) or old-aged (OA, 36 months). The bipolar cell terminal in OA zebrafish exhibited a two-fold reduction in number of synaptic ribbons, an increased ribbon length, and a decrease in local Ca2+ signals at the tested ribbon location, with little change in the overall magnitude of the calcium current or exocytosis in response to brief pulses. Staining of the synaptic ribbons with antibodies specific for PKCa revealed shortening of the inner nuclear and plexiform layers (INL and IPL). These findings shed light on age-related changes in the retina that are related to synaptic ribbons and calcium signals.
摘要：
与年龄相关的视力障碍引起的全球健康关注突出了需要进一步研究，重点是衰老过程中发生的视觉变化。迄今为止,已经确定了与衰老相关的多种感官改变，包括内部毛发耳蜗细胞的形态和功能变化，光感受器，和视网膜神经节细胞.虽然一些年龄相关的形态学变化是已知发生在视网膜的杆状双极细胞，它们对这些细胞的影响以及它们通过带状突触与其他细胞的连接仍然难以捉摸。为了研究衰老对棒双极细胞及其带状突触的影响，我们比较了突触钙电流，钙动力学，和中年斑马鱼(Daniorerio)的胞吐作用(MA，18个月)或老年人(OA，36个月）。OA斑马鱼的双极细胞末端显示突触带数量减少了两倍，增加丝带长度，以及测试色带位置的局部Ca2+信号减少，对短暂脉冲的响应，钙电流或胞吐作用的总幅度几乎没有变化。用PKCa特异性抗体染色突触带显示内核和丛状层（INL和IPL）缩短。这些发现揭示了与突触带和钙信号相关的视网膜年龄相关的变化。
