Astrocytic exocytosis vesicles and glutamate: A high‐resolution immunofluorescence study

Abstract
Physiological evidence has demonstrated that cultured astrocytes can release glutamate via Ca2+‐dependent mechanisms. Also, glutamate released from astrocytes in the hippocampal slice interferes with synaptic neurotransmission. Since these observations suggest vesicular glutamate release from astrocytes, the presence of glutamate‐containing exocytosis vesicles was investigated. We applied immunofluorescence techniques combined with high‐performance deconvolution microscopy, which yields a resolution of 2+‐dependent glutamate release from astrocytes, possibly occurring at defined sections of the cell membrane and at filopodia. However, since vGluTs and exocytosis markers are classically restricted to nerve terminals in the CNS, glutamate release from astrocytes in the CNS remains to be studied.