Reversal of synaptic vesicle docking at central synapses

We used quantitative fluorescence imaging of vesicles labeled with membrane -soluble dyes to determine rates of undocking and spontaneous exocytosis of vesicles docked to the active zone of hippocampal synapses in culture. Ind ividual vesicles undock about once per two minutes and spontaneously exocyt ose about once per eight minutes. Thus, not only does undocking occur, but it is over threefold faster than spontaneous fusion.