Regulation of spontaneous glutamate release by extracellular calcium

Synaptic vesicles fuse with nerve terminal plasma membrane not only in response to an action potential, but also spontaneously. Such spontaneous events contribute to neuronal baseline noise, maintain synaptic strength, and can induce and modulate action potential firing in inhibitory neurons. The mechanisms controlling this mode of synaptic transmission remain largely unknown. The overall objective of these studies was to determine mechanisms controlling spontaneous vesicle fusion.