Our previous study showed that the disturbed Glu-Gln-GABA cycle occurred in the striatum of PD rats and bFGF treatment might alleviate PD symptoms through regulating these alterations (Zheng et al., 2016), another study reported that there was a significantly decreased striatal level of Glu in LID rats (Wang et al., 2018). Here, FGF2 is linked to Parkinson disease.