In an animal model of Parkinson's disease, Korean red ginseng could improve the behavioral impairment of mice in the pole test, inhibit dopaminergic neuronal death, and decrease cyclin-dependent kinase 5 (Cdk5) and p25 expressions as well as increase p35 expression in the substantia nigra and striatum of MPTP-induced mice [146]. Here, CDK5 is linked to Parkinson disease.