Departments of Cell Biology and Physiology, Biomedical Engineering, Washington University, St. Louis, MO 63110, USA.
Departments of Cell Biology and Physiology, Biomedical Engineering, Washington University, St. Louis, MO 63110, USA.
Neuron. 2017 Apr 5;94(1):65-73.e3. doi: 10.1016/j.neuron.2017.03.006. Epub 2017 Mar 23.
The number and availability of vesicle release sites at the synaptic active zone (AZ) are critical factors governing neurotransmitter release; yet, these fundamental synaptic parameters have remained undetermined. Moreover, how neural activity regulates the spatiotemporal properties of the release sites within individual central synapses is unknown. Here, we combined a nanoscale imaging approach with advanced image analysis to detect individual vesicle fusion events with ∼27 nm localization precision at single hippocampal synapses under physiological conditions. Our results revealed the presence of multiple distinct release sites within individual hippocampal synapses. Release sites were distributed throughout the AZ and underwent repeated reuse. Furthermore, the spatiotemporal properties of the release sites were activity dependent with a reduction in reuse frequency and a shift in location toward the AZ periphery during high-frequency stimulation. These findings have revealed fundamental spatiotemporal properties of individual release sites in small central synapses and their activity-dependent modulation.
囊泡释放位点的数量和可用性是控制神经递质释放的关键因素；然而，这些基本的突触参数仍未确定。此外，神经活动如何调节单个中枢突触内释放位点的时空特性尚不清楚。在这里，我们结合纳米尺度成像方法和先进的图像分析，在生理条件下，在单个海马突触上以约 27nm 的定位精度检测到单个囊泡融合事件。我们的结果表明，单个海马突触内存在多个不同的释放位点。释放位点分布在整个 AZ 区，并经历重复使用。此外，释放位点的时空特性依赖于活动，在高频刺激期间，重复使用频率降低，位置向 AZ 外围转移。这些发现揭示了小中枢突触中单个释放位点的基本时空特性及其活动依赖性调节。
