Since Cdk5/p25 hyperactivity involves in the progression of PD and the neurotoxicity of MPTP induced mice (Nakamura et al., 1997; Alvira et al., 2008; Sundaram et al., 2012), we evaluated whether the effects of CIP in MPTP/p induced PD model were based on the inhibition of Cdk5/p25 hyperactivity. The gene discussed is CDK5; the disease is Parkinson disease.