GDNF and Parkinson disease: In 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced PD mice, HDACs inhibitors, such as sodium valproate and sodium butyrate, increased the expression of glial cell-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) in astrocytes, while histone H3 acetylation was significantly increased [14–16].