G-protein coupled receptor for glutamate. Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of down-stream effectors. Signaling inhibits adenylate cyclase activity. Interacts with PICK1. Prominent expression in olfactory bulb, pontine gray, lateral reticular nucleus of the thalamus, and piriform cortex. Less abundant expression incerebral cortex, hippocampus, cerebellum, and mammillary body. Belongs to the G-protein coupled receptor 3 family.