Presynaptic localization of α-synuclein in excitatory neurons.

(A, B) Confocal images of double immunostaining for α-synuclein and synaptotagmin. The region marked by a white square in A is magnified in B. Arrowhead in B indicates the presynapse, expressing both α-synuclein and synaptotagmin. However, there are some synaptotagmin-positive synapses lacking α-synuclein (arrow). (C, D) Confocal images of double immunostaining for α-synuclein and vGluT-1, an excitatory neuronal marker protein. The region marked by a white square in C is magnified in D. α-Synuclein is colocalized with vGluT-1 in D (arrowheads). Three independent cultures were performed and colocalization between α-synuclein and vGluT-1 was reproducibly confirmed. Panel C was subjected to the quantitative colocalization analysis shown in Fig. S2. Scale bars: 10 µm in A and C; 5 µm in B and D.