α-Synuclein facilitates dopamine release during burst firing of substantia nigra neurons in vivo

-Synuclein is expressed at high levels at presynaptic terminals, but defining its role on neurotransmission under physiologically-relevant conditions has proven elusive. We report that -synuclein is responsible for a rapid facilitation of dopamine release during action potential bursts in vivo. This occurs in tandem with a far slower stimulus-dependent depression, appears to be independent of the presence of {beta}- and {gamma}-synucleins or effects on presynaptic calcium and is consistent with a role for synucleins in the enhancement of synaptic vesicle fusion and turnover. The results indicate that the presynaptic effects of -synuclein are dependent on specific patterns of neuronal activity.