|Neuron A (transmitting) to neuron B (receiving). In a neuron,
synaptic vesicles (or neurotransmitter vesicles) store various
neurotransmitters that are released at the synapse. The release
is regulated by a voltage-dependent calcium channel. Vesicles
are essential for propagating nerve impulses between neurons and
are constantly recreated by the cell. The area in the axon that
holds groups of vesicles is an axon terminal or "bouton". Up to
130 vesicles can be released per bouton over a ten-minute period
of stimulation at 0.2 Hz.1 In the human brain region V1 synaptic
vesicles have an average diameter of 39.5 nanometers with a
standard deviation of 5.1 nanometers.2 With the advent of modern
electron microscopic techniques in the early 1950s, nerve
endings were found to contain a large number of electron-lucent
vesicles.34 The term synaptic vesicle was first introduced by De
Robertis and Bennett in 1954.5 This was shortly after
transmitter release at the frog neuromuscular junction was found
to induce postsyna