A highly Ca2+-sensitive pool of vesicles contributes to linearity at the rod photoreceptor ribbon synapse
A highly Ca2+-sensitive pool of vesicles contributes to linearity at the rod photoreceptor ribbon synapse
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DOI：
10.1016/s0896-6273(04)00254-5
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发表时间：
2004-05-27
期刊：
影响因子：
16.2
通讯作者：
Heidelberger, R
中科院分区：
文献类型：
--
作者：
Thoreson, WB;Rabl, K;Heidelberger, R
对突触传递特性的研究只在少数突触上进行过。我们结合生理学和超微结构技术分析了视杆细胞的胞吐作用。在其他带状突触，我们发现，杆表现出快速的释放动力学，和可释放池中的囊泡的数量是可比的带状风格的活动区拴系的囊泡的数量。然而，与其他以前研究的神经元，我们确定了一个高度调用敏感池的可释放囊泡与胞吐率和[Ca2+]之间的关系相对较浅，这是近线性的假定的生理范围内的终端[Ca2+]。释放的低阶[Ca2+]依赖性促进Ca2+进入和胞吐之间的线性关系，这允许杆在视觉中的第一突触处以高保真度中继关于照明中的小变化的信息。
Studies of the properties of synaptic transmission have been carried out at only a few synapses. We analyzed exocytosis from rod photoreceptors with a combination of physiological and ultrastructural techniques. As at other ribbon synapses, we found that rods exhibited rapid kinetics of release, and the number of vesicles in the releasable pool is comparable to the number of vesicles tethered at ribbon-style active zones. However, unlike other previously studied neurons, we identified a highly Call-sensitive pool of releasable vesicles with a relatively shallow relationship between the rate of exocytosis and [Ca2+], that is nearly linear over a presumed physiological range of intra-terminal [Ca2+]. The low-order [Ca2+] dependence of release promotes a linear relationship between Ca2+ entry and exocytosis that permits rods to relay information about small changes in illumination with high fidelity at the first synapse in vision.