Synergy between l-DOPA and a novel positive allosteric modulator of metabotropic glutamate receptor 4: Implications for Parkinson's disease treatment and dyskinesia

► We characterized a novel mGlu4 receptor positive allosteric modulator: Lu AF21934 (AF). ► AF inhibits corticostriatal glutamatergic transmission (in vitro electrophysiology). ► AF alleviates haloperidol-induced catalepsy. ► l-DOPA + AF treatment improves akinesia & prevents dyskinesia in hemiparkinsonian rats. ► Such systemic treatment has a potential for antiparkinsonian clinical therapy.