MinireviewCycling the Synapse : Scenic versus Direct Routes for Vesicles

siently connects the vesicle interior to the extracellular What happens to synaptic vesicles after they release space. Once the pore closes, the empty vesicle either their neurotransmitter content? Recent work on a varidetaches from the active zone or it remains in place and ety of synaptic systems shows that there is no single refills with neurotransmitter for another round of release answer to this question. Rather, it seems that neurons (kiss-and-stay). In either case, recently recycled vesicles use a variety of methods to retrieve and reuse synaptic occupy a privileged location near the active zone, which vesicles after they have undergone exocytosis. The would neatly explain their preferential reuse. Is there exchallenge now is to establish the molecular mechaperimental evidence to support this spatial hypothesis for nisms and to decipher the rules that govern which the rapidly cycling subset? At hippocampal synapses, recycling pathway is used in a given functional context. cently recycled vesicles do tend to be somewhat preferen-