GRM4 and major depressive disorder: Additionally, miR-1202 has been shown to be a regulatory factor of the metabotropic GRM4 gene, which is involved in dopaminergic, glutamatergic, GABAergic, and serotonergic neurotransmission, and this finding is important in the context of studies indicating that down-regulation of miR-1202 in the prefrontal cortex of subjects with depression is negatively correlated with GRM4 expression [35].