Università Vita-Salute San Raffaele, Milan, 20132, Italy.
Neurobiology of Learning Unit, Division of Neuroscience, Scientific Institute Ospedale San Raffaele, Milan, 20132, Italy.
Nat Commun. 2017 Oct 31;8(1):1229. doi: 10.1038/s41467-017-01335-4.
Ideally, elucidating the role of specific brain circuits in animal behavior would require the ability to measure activity at all involved synapses, possibly with unrestricted field of view, thus even at those boutons deeply located into the brain. Here, we introduce and validate an efficient scheme reporting synaptic vesicle cycling in vivo. This is based on SynaptoZip, a genetically encoded molecule deploying in the vesicular lumen a bait moiety designed to capture upon exocytosis a labeled alien peptide, Synbond. The resulting signal is cumulative and stores the number of cycling events occurring at individual synapses. Since this functional signal is enduring and measurable both online and ex post, SynaptoZip provides a unique method for the analysis of the history of synaptic activity in regions several millimeters below the brain surface. We show its broad applicability by reporting stimulus-evoked and spontaneous circuit activity in wide cortical fields, in anesthetized and freely moving animals.
理想情况下，阐明特定脑回路在动物行为中的作用需要能够测量所有相关突触的活动，可能需要不受限制的视野，因此即使是那些位于大脑深部的突触点。在这里，我们介绍并验证了一种有效的方案，用于体内报告突触小泡循环。这是基于SynaptoZip，一种在囊泡腔中表达的基因编码分子，其中部署了一个诱饵部分，设计用于在胞吐作用时捕获一个标记的外来肽，Synbond。由此产生的信号是累积的，并存储在单个突触处发生的循环事件的数量。由于这种功能性信号是持久的，并且可以在线和事后进行测量，因此 SynaptoZip 为分析位于脑表面以下几毫米的区域的突触活动历史提供了一种独特的方法。我们通过报告麻醉和自由活动动物的宽皮质场中的刺激诱发和自发电路活动，展示了其广泛的适用性。
