Enables G protein-coupled enkephalin receptor activity and receptor serine/threonine kinase binding activity. Involved in several processes, including eating behavior; phospholipase C-activating G protein-coupled receptor signaling pathway; and regulation of sensory perception of pain. Located in several cellular components, including dendrite membrane; membrane raft; and postsynaptic membrane. Is active in neuronal dense core vesicle and spine apparatus. Is integral component of postsynaptic density membrane; integral component of presynaptic membrane; and integral component of synaptic vesicle membrane. Used to study myocardial infarction. Orthologous to human OPRD1 (opioid receptor delta 1). [provided by Alliance of Genome Resources, Apr 2022]