Cycling the synapse: scenic versus direct routes for vesicles.

What happens to synaptic vesicles after they release their neurotransmitter content? Recent work on a variety of synaptic systems shows that there is no single answer to this question. Rather, it seems that neurons use a variety of methods to retrieve and reuse synaptic vesicles after they have undergone exocytosis. The challenge now is to establish the molecular mechanisms and to decipher the rules that govern which cycling pathway is used in a given functional context.