Metabotropic Glutamate (mGlu) group III receptors are members of the metabotropic class of glutamate receptors, which also includes mGlu group I and mGlu group II receptors. Group III receptors are divided into four subtypes, mGlu4, mGlu6, mGlu7 and mGlu8. mGlu group III receptors are coupled to Gi/o, which inhibits adenylyl cyclase, decreasing the formation of cAMP. These receptors are involved in spatial learning and memory, and umami taste (mGlu4), stimulation of photoreceptors (mGlu6), long term depression (mGlu7) and presynaptic inhibition in the perforant pathway (mGlu8). The human genes for mGlu4, mGlu6, mGlu7 and mGlu8 receptors have been localized to chromosomes 6 (6p21.3), 5 (5q35), 3 (3p26-p25) and 7 (7q31.3-q32.1) respectively.
