ECH improved the viability of MPP+-treated cell in vivo, and increased the expression of tyrosine hydroxylase (TH), GDNF, GDNF family receptor α (GFRα1) and Ret in cells of substantia nigra (SN) of MPTP-induced PD mouse model (Xu et al., 2016). Here, GFRA1 is linked to Parkinson disease.