Immunogen: Synthetic 18 amino acid peptide from 3rd extracellular domain of human Delta Opioid Receptor. Percent identity with other species by BLAST analysis: Human, Gorilla, Monkey, Marmoset, Dog, Elephant, Panda, Horse, Rabbit (100%); Mouse, Rat, Bovine, Bat, Hamster (94%); Pig, Opossum (83%).