Presynaptic regulation of quantal size: K + /H + exchange stimulates vesicular glutamate transport

The authors report that rat brain glutamatergic synaptic vesicles express monovalent cation/H + exchangers that convert the Δψ of the proton electrochemical gradient into Δψ. They find that this K + /H + exchange stimulates the accumulation of glutamate into vesicles, regulating glutamate release and thus synaptic transmission.