The pathological hallmark of Parkinson disease is a widespread distribution of the aggregated α-synuclein (α-Syn) proteins in the inclusions known as Lewy bodies. This widespread distribution of α-Syn oligomer is involved in intercellular transport between neurons and glial cells. However, it is unclear whether other blood-brain barrier (BBB) comprising cell types (brain endothelial cells, pericytes and astrocytes) contribute this process. Here, we investigated the ability of BBB comprising cell types, especially brain pericytes to take up α-Syn oligomer. We confirmed that HiLyte488-conjugated α-Syn (AnaSpec Inc.) contained monomeric (17 kDa) and oligomeric (> 17 kDa) α-Syn by Western blot. Oligomeric α-Syn uptake by pericytes at 1 hr was decreased during a 24-h period, but other cell types did not show a similar reduction. In the presence of a lysosome inhibitor bafilomycin A1 or P-glycoprotein (P-gp) inhibitor cyclosporin A (CsA), the intracellular accumulation of oligomeric α-Syn in pericytes was increased. In addition, CsA-induced increase of intracellular oligomeric α-Syn was degraded at 48 h. These results suggest that oligomeric α-Syn is degraded in pericytes and P-gp is involved in the efflux of oligomeric α-Syn from pericytes. The inhibition of P-gp by CsA would facilitate the degradation of oligomeric α-Syn by pericytes.