The locomotor impairment is a common symptom in PD progression; Arnold and Salvatore indicate that short-term exercise can attenuate the locomotor impairment in aging rats via increasing nigral glial cell line-derived neurotrophic factor (GDNF) receptor, GFR-α1, and EAAC1 expression in conjunction with increased nigral tyrosine hydroxylase expression [86]. This evidence concerns the gene TH and Parkinson disease.