题 目：Small electrochemcial sensors and single cells: zeptomoles, milliseconds, and the nature of reality in exocytosis
报告人：Andrew G Ewing教授
主持人：田阳 教授
时 间：10月27日10:00
地 点：闵行校区实验D楼207报告厅
报告人简介：Andrew G Ewing教授是瑞典哥德堡大学教授，国际上分析化学、单细胞分析、神经化学领域资深的科学家之一，在电化学、质谱等分析方法在单细胞分析、成像的应用等领域的研究成果突出。现任美国化学会著名刊物《Analytical chemistry》副主编，在国际著名杂志发表高水平学术论文多篇，专著多篇。
报告内容简介：We have used ultrasmall electrodes to measure neurotransmitter release from single cells, a method that has become commonplace after twenty years. Here, we have analyzed amperometric peaks corresponding to release at PC12 cells and found stable plateau currents during the decay of the peaks (post-spike feet), indicating closing of the vesicle after incomplete release of the vesicular content. We propose a process for most exocytosis events where the vesicle partially opens to release transmitter and then closes directly again, leaving the possibility for both a stable pre and post spike feet to be observed with amperometry. In addition, those experiments correlate well with those from the electrochemical cytometry method we have concurrently developed to count electroactive molecules in individual synaptic vesicles in directly sampled populations from cells or brain tissue. With this method we have compared the total numbers of molecules in vesicles to those released and only a fraction of these are released both in the PC12 cell model and in mammalian brains. Partial release is important in that it produces a new pharmaceutical paradigm and could be important in understanding learning and memory. It also makes it clear that the dynamics of vesicle opening, controlled largely by lipids, might be an important characteristic in neurotransmission. The interplay of lipids and proteins mitigating open and closed exocytosis might form part of the basis for short-term memory.