生物物理与神经生物学前沿学术报告

报告题目:     Real-time Three-dimensional, Nanometer-Accuracy Tracking of

Single Synaptic Vesicles in Live Hippocampal Neurons

报告人:    Hyokeun Park, Ph.D

                 Professor of Division of Life Science and Department of Physics

                The Hong Kong University of Science and Technology

时间：    2018年12月18日（周二），上午：10:30-11:30

地点：西区生物楼429会议室

主办单位：中国科学院脑功能与脑疾病重点实验室

中国科学技术大学生命科学学院

合肥微尺度物质科学国家研究中心集成影像中心

报告简介：

The position and movement of synaptic vesicles in presynaptic terminals are important for synaptic transmission. However, accurate three-dimensional tracking of single synaptic vesicles in presynaptic terminals has remained a challenge. Using dual-focus imaging optics, we have been able to track quantum dot (Qdot)-labeled single vesicles in3D, with an accuracy of 20-30 nm in 10 Hz imaging. Using different loading protocols, we are able to track the dynamics of synaptic vesicles derived from either the readily releasable pool or total recycling pool. Also two different modes of exocytosis - full-collapse-fusion and kiss-and-run – could be distinguished using the degree of quenching of quantum dot photoluminescence by micromolar trypan blue.

In order to determine the location of releasing position relative the center of the active zone, we localized the centroids of spectrally separable markers, FM 4-64 (presynaptic sites) and PSD 95-GFP (postsynaptic sites) in 3D using the same methods as Qdot loaded vesicles. The vector connecting these centroids approximated the central axis of the synapse, and allowed us to estimate the degree to which fusion occurred at positions away from the center of the active zone. We found that synaptic vesicles undergoing kiss-and-run tend to fuse close to the center of the active zone whereas vesicles undergoing full-collapse fusion tend to fuse all around the synapse. This difference of fusion mode may be related to the difference in the spatial distribution of AMPA and NMDA receptors, implying the relation between fusion mode and synaptic transmission.