SLC18A2 and Parkinson disease: The animals that presented a lower score in the CR (indicating improvement in their PD signs) had more TH-ir OD in the putamen (Pearson's correlation; r2 = 0.320, P = 0.002), as well as more TH (r2 = 0.338, P = 0.024) and VMAT2 (r2 = 0.689, P = 0.003) positive neurons in the SN.