Following the MPTPp administrations, the mRNA expression of tyrosine hydroxylase (TH, a marker of dopaminergic neuron) in substantia nigra was dramatically decreased (42.5 and 68.2% in the discovery and replication phase, respectively; 55.4%, total) (Fig 1), validating the model of PD in mice. The gene discussed is TH; the disease is Parkinson disease.