AUTHOR=Hain Paul Jakob Habakuk , Moser Tobias 

TITLE=Optical measurement of glutamate release robustly reports short-term plasticity at a fast central synapse

JOURNAL=Frontiers in Molecular Neuroscience

VOLUME=Volume 17 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/molecular-neuroscience/articles/10.3389/fnmol.2024.1351280

DOI=10.3389/fnmol.2024.1351280

ISSN=1662-5099

ABSTRACT=Recently developed fluorescent neurotransmitter indicators have enabled direct measurements of neurotransmitter in the synaptic cleft. Precise optical measurements of neurotransmitter release may be used to make inferences about presynaptic function independent of electrophysiological measurement techniques. Here, we express iGluSnFR, a genetically encoded glutamate reporter in mouse spiral ganglion neurons to compare electrophysiological and optical readouts of presynaptic function and short-term synaptic plasticity at the endbulb of Held synapse. We conclude that iGluSnFR robustly and approximately linearly reports glutamate release from the endbulb of Held during synaptic transmission and allows assessment of short-term plasticity during high-frequency train stimuli. Furthermore, we show that iGluSnFR expression slightly alters the time course of spontaneous postsynaptic currents, but is unlikely to impact measurements of evoked synchronous release of many synaptic vesicles.