After the use of the antagonist of mGluR5, as is shown in Figure 2, coadministration of MTEP (5 mg/kg, i.p.)with L-Dopa (25 mg/kg, i.p.)did not develop severe dyskinesia over the 14-day treatment; the antagonization of the mGluR5 downregulated the overactivated phosphorylation of the ERK1/2 via PKC/MEK/ERK1/2 pathways. Here, GRM5 is linked to drug-induced dyskinesia.