Eddings Chelsy R, Watanabe Shigeki
Department of Cell Biology, The Johns Hopkins University, Baltimore MD, 21205, USA.
Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University, Baltimore MD, 21205, USA.
bioRxiv. 2025 Jun 8:2025.06.06.658279. doi: 10.1101/2025.06.06.658279.
Neural circuitry depends on excitatory and inhibitory regulation of activity to yield functional outputs. However, examinations of synaptic vesicle recycling have focused heavily on excitatory synapses, leaving many questions unanswered for inhibitory synapse dynamics. Here we show that both excitatory and inhibitory cortical synapses contain depots of a protein essential for ultrafast endocytosis, Dynamin 1xA, at a region immediately next to the active zone where ultrafast endocytosis takes place. Using zap-and-freeze time-resolved electron microscopy in mouse acute cortical slices, we observe uncoated pits reminiscent of ultrafast endocytic intermediates appearing post-stimulus at putative inhibitory synapses. These findings suggest that excitatory and inhibitory synapses may perform similar modes of endocytosis.
神经回路依赖于对活动的兴奋性和抑制性调节来产生功能性输出。然而，对突触小泡循环的研究主要集中在兴奋性突触上，关于抑制性突触动力学仍有许多问题未得到解答。在这里，我们表明，兴奋性和抑制性皮质突触在紧邻发生超快内吞作用的活性区的区域都含有一种对超快内吞作用至关重要的蛋白质——发动蛋白1xA的储存库。利用小鼠急性皮质切片中的电刺激和冷冻时间分辨电子显微镜，我们在假定的抑制性突触中观察到了刺激后出现的类似超快内吞中间体的无包被小窝。这些发现表明，兴奋性和抑制性突触可能执行相似的内吞模式。
