Summary of mGlu receptor subtype expression, signaling, and interacting partners

GroupReceptorCNS ExpressionSynaptic LocalizationG protein CouplingPrimary Signaling PathwaysInteracting Partners
Group ImGlu1Widespread in neuronsPredominantly postsynapticPrimarily Gαq/11 noncanocial Gαi/0, GαsPLCβ → IP3 + DAG hydrolysis phospholipase D MAPK/ERK mTOR/p70 S6 kinaseActivates NMDA receptors activates Ca2+ channels (e.g., Cav2.1) activates CaMKIIα
mGlu5Widespread in neurons
Group IImGlu2Widespread in neuronsPresynaptic and postsynapticPrimarily Gαi/0Inhibition of adenylyl cyclase MAPK/ERK IP3-PI3 kinaseActivation of K+ channels inhibition of voltage-gated Ca2+ channels (e.g., N- type)
mGlu3Widespread in neurons, astrocytes
Group IIImGlu4Widespread in neurons, high in cerebellumPredominantly presynapticPrimarily Gαi/0 noncanocial Gαq/1Inhibition of adenylyl cylcase MAPK/ERK IP3 (mGlu7) stimulation of cGMP phosphodiesterase (mGlu6)Activation of K+ channels inhibition of Ca2+ channels (P/Q subtype)
mGlu6Retina, select neuron populations, microgliaPostsynaptic in retinal cells
mGlu7Widespread in neuronsActive zone of presynaptic terminals
mGlu8Lower and more restricted expression than mGlu4/7Predominantly presynaptic
  • caMKII-alpha, Calcium/calmodulin-dependent kinase II; cGMP, cyclic guanosine monophosphate; DAG, diacyl-glycerol; G protein i/o alpha subunit; G protein Gs alpha subunit; G protein Gq alpha subunit; IP3, inositol 1,4,5-trisphosphate; MAPK/ERK, mitogen-activated protein kinase/extracellular receptor kinase; mTOR, mammalian target of rapamycin; PI3 kinase, phosphatidyl inositol 3-kinase; PLCβ, phospholipase Cβ; p70-S6 kinase, P70-S6; P/Q, P/Q-type calcium channel.