Morphological correlates of functionally defined synaptic vesicle populations

Abstract

By combining photoconversion of FM1-43-stained vesicles and electron microscopy of hippocampal synapses, we find evidence that the population of morphologically docked synaptic vesicles corresponds to the release-ready neurotransmitter quanta. Furthermore, those synaptic vesicles that are participating in cycles of exo- and endocytosis tend to be closer to the active zone than vesicles that are being held in reserve.