Moreover, upon specific blocking of P-gp using zosuquidar increased intracellular accumulation of FLZ in rCMECs in a dose-dependent manner (Figure S2) and resulted in significantly lower efflux ratio of FLZ in the BBB models from either normal (Figure 6Ad, Figure S2, Table S1) or Parkinson's disease rats (Figure 6Bd, Table S1). This evidence concerns the gene PGP and Parkinson disease.