Central Synapses Release a Resource-Efficient Amount of Glutamate

Why synapses release a certain amount of neurotransmitter is poorly understood. Here we combine patch-clamp electrophysiology with computer simulations to estimate how much glutamate is discharged at two distinct central synapses of the rat. We find that, regardless of some uncertainty over synaptic microenvironment, synapses generate the maximal current per released glutamate molecule while maximizing signal information content. Our result suggests that synapses operate on a principle of resource optimization.