Synaptic vesicle exocytosis. Does a lingering kiss lead to fusion?

Direct optical measurements of single synaptic vesicles undergoing exocytosis at a synapse reveal rapid and complete transfer of membrane marker from the vesicle to the plasma membrane (; this issue of Neuron). Contact between the two membranes is consistent with free lipid exchange, such as might result from full fusion of the vesicle and plasma membranes.