In this aspect, KO mice for P-glycoprotein have shown an increased accumulation of neurotoxin ivermectin and the carcinostatic drug vinblanstine in the brain, suggesting the importance of P-glycoprotein in the clearance of toxic substances and a possible BBB disruption in PD (Schinkel et al., 1994). This evidence concerns the gene ABCB1 and Parkinson disease.