High Quality Content by WIKIPEDIA articles! The active zone is a term first used by Couteaux and Pecot-Dechavassinein in 1970 to define the site of neurotransmitter release. Two neurons make contact through structures called synapses allowing them to communicate with each other. As shown in the diagram on the right, a synapse consists of the presynaptic bouton of one neuron which stores vesicles containing neurotransmitter (uppermost in the picture) and a second, postsynaptic neuron which bears receptors for the neurotransmitter (at the bottom). When an action potential reaches the presynaptic bouton, the contents of the vesicles are released into the synaptic cleft and the released neurotransmitter travels across the cleft to the postsynaptic neuron (the lower structure in the picture) and activates the receptors on the postsynaptic membrane.