Seeing glutamate at central synapses

Glutamate is the major fast excitatory neurotransmitter in the nervous system, and researchers have for decades pursued tools for monitoring glutamate release in real time. Optical reporters, primarily genetically-encoded glutamate sensors, have developed into the predominant method, particularly following the advent of the intensity-based glutamate-sensing fluorescent reporter (iGluSnFR). Several variants have been developed to improve the performance of iGluSnFR in brightness, kinetics and spectral range. Following the targeting principle of other sensors for neurotransmission, iGluSnFR mutants tethered to pre- or postsynaptic targeting proteins should show enhanced properties for detecting glutamate release at central synapses.