Neurons in the nervous system organize into complex networks and their functions are precisely controlled. The most important means for neurons to communicate with each other is transmission through chemical synapses, where the release of neurotransmitters by the presynaptic nerve terminal of one neuron influences the function of a second neuron. Since the discovery of chemical neurotransmission by Otto Loewi in the 1920s, great progress has been made in our understanding of mol- ular mechanisms of neurotransmitter release. The last decade has seen an explosion of knowledge in this field. The...