receptor | LDL receptor | Receptor (biochemistry) | Continuous erythropoietin receptor activator | GABA receptor | Epidermal growth factor receptor | NMDA receptor | Sensory receptor | receptor (biochemistry) | metabotropic glutamate receptor | 5-HT2A receptor | VLDL receptor | TGF beta receptor 2 | receptor antagonist | epidermal growth factor receptor | 5-HT receptor | RAR-related orphan receptor alpha | opioid | Metabotropic glutamate receptor 5 | Metabotropic glutamate receptor 2 | G protein-coupled receptor | AMPA receptor | Adenosine A1 receptor | Toll-like receptor | TNF receptor associated periodic syndrome | taste receptor | Sigma-1 receptor | Receptor antagonist | Receptor activity-modifying protein | Pancreatic polypeptide receptor 1 |
It is an agonist of the opioid receptors, with evidence suggesting it serves as the endogenous ligand of the μ-opioid receptor, the same receptor to which the chemicals extracted from opium, such as morphine, have their analgesic and addictive effects (indeed, the μ-opioid receptor was named based on its most renowned ligand, morphine).