The Drosophila active zone architecture: combining confocal, STED and transmission electron microscopy

Abstract

Synapses form by an asymmetric association of highly specialized membrane domains: transmitter receptors at the postsynaptic density sense the neurotransmitter signal, while the synaptic vesicles release their content at the presynaptic active zone. Here, macromolecular specializations have evolved that are visible in the transmission electron microscope and therefore are referred to as electron dense projections or dense bodies. Dependent on their transmission kinetics, they show a high variation in shape and size. Many components of the release machinery have already been identified. However, the molecular composition of such dense bodies is in most cases still completely unknown.