Vesicle recycling and reuse is essential in maintaining synaptic transmission.In spite of accumulative studies, it remains elucidated that how many vesicles involve in recycling, how long and how fast a vesicle can be reused after exocytosis.We made the whole cell recording of the excitatory postsynaptic currents (EPSCs) at a central synapse, the Calyx of Held, under the long duration of stimulation in the presence of folimycin, a vesicular ATPase inhibitor to annihilates the H+ gradient and block glutamate refilling of synaptic vesicles.It was confirmed that vesicles at the Calyceal synpases do recycle and reuse after exocytosis.During long trains of 20 Hz or 50 Hz stimulation, the evoked EPSCs can be rapidly depressed and finally mostly vanished, implying the depletion of the recycling pool.