Enables G protein-coupled receptor activity involved in regulation of postsynaptic membrane potential and neurotransmitter receptor activity involved in regulation of postsynaptic cytosolic calcium ion concentration. Involved in several processes, including calcium-mediated signaling using intracellular calcium source; cellular response to amyloid-beta; and modulation of age-related behavioral decline. Acts upstream of or within learning; locomotory behavior; and regulation of long-term neuronal synaptic plasticity. Located in several cellular components, including Schaffer collateral - CA1 synapse; neuron projection; and plasma membrane. Is expressed in central nervous system and retina. Used to study schizophrenia. Orthologous to human GRM5 (glutamate metabotropic receptor 5). [provided by Alliance of Genome Resources, Apr 2022]