Revisiting Katz's Quantal Release Theory by Observing Synaptic Transmission at Single Synapse

Revisiting Katz's Quantal Release Theory by Observing Synaptic Transmission at Single Synapse
Date & Time: 
Friday, December 15, 2017 -
12:00 to 13:00
Jianyuan Sun, Institute of Biophysics, Chinese Academy of Sciences
Room 385, Geography Building, 3663 Zhongshan Road North, Shanghai
At synaptic nerve terminals, neurotransmitter is packaged into vesicles and released either spontaneously or in response to presynaptic action potential invasion. In their seminal work, Katz and colleagues established the quantal nature of this process, whereby the basic unit of neurotransmission is the quantal event detected postsynaptically as a small all-or-none miniature postsynaptic potential or current (mini), in response to the neurotransmitter release from a single vesicle. However, justification of the quantal nature of minis has never been completed as minis are not identical in size and do not follow the principle of invariance. Here, we selectively study the minis from single active zone contained axo-somatic synapses using whole-cell recording and quantitative analysis. It was found that the amplitude of spontaneous and evoked miniature events from single synapses displayed large variance and were some multiple of a subunit. Our study reveals the large scope of regulation in single quantal synaptic transmission and suggests the higher capacity of synaptic information processing than Katz's quantal theory predicted.
Prof. Jianyuan Sun received his Ph.D. degree in Physiology from East China Normal University. He did his postdoctoral study with Dr. Wolf Almers in Max-Planck Institute for Medical Research during 1997-1999 and worked as research associate with Dr. Ling-Gang Wu in Washington University at St. Louis where he honored James O’Leary Prize for Outstanding Research in Neuroscience during 1999-2002. In 2002, Dr. Sun joined the faculty at the Center for Basic Neuroscience at UT Southwestern Medical Center led by Dr. Thomas Südhof and he received the NARSAD young investigator award in 2004. In 2008, Dr. Sun became principal investigator and professor with Hundred Talents scholarship in the Institute of Biophysics at Chinese Academy of Sciences and awardee of the Distinguished Young Scholars by the National Natural Science Foundation. He was appointed as director of Neuroscience Program, University of Chinese Academy of Sciences in 2015. He is currently the Editorial board member of《SYNAPSE》journal and Council member of the Chinese Neuroscience Society. Prof. Sun’s research interest is to elucidate the molecular and biophysical principles of synaptic transmission and its impacts in neuronal information encoding. Specifically, he aims to understand the mechanisms and consequences of transmitter release in single vesicle, single active zones and single neuron perspectives.
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