Notably, increasing evidence supports the contribution of mGluR1-dependent mechanisms in the pathogenesis of neurological and psychiatric disorders, such as schizophrenia, Parkinson’s disease (PD), addiction, and autism [87,132,133,134], which are either characterized by alterations in midbrain DA transmission and also linked to NRG1/ErbB dysfunctions [13,46,135,136,137]. Here, GRM1 is linked to Parkinson disease.