GRM1 and schizophrenia: Moreover,we demonstrated that mGlu1 PAMs inhibit dopamine releasein an endocannabinoid-dependent manner, as do M4 PAMs.11−13 Human genetic data also support mGlu1 as a viable targetfor schizophrenia, with numerous loss-of-function single nucleotidepolymorphisms (SNPs) in GRM1, the gene-encoding mGlu1 in schizophrenia and bipolar patients.