α-Synuclein (ASN) is richly abundant in the central nervous system, particulary in pre- synaptic terminals. Among many functions, ASN plays a crucial role in regulation of dopaminergic system. In physiological conditions, soluble ASN is involved in maintenance of dopamine (DA) homeostasis in the central nervous system. This protein regulates DA level and biosynthesis by inhibition of the tyrosine hydroxylase. It also influences DA storage and release from synaptic ve- sicles as well as DA uptake by its transporter (DAT).