Opioid receptors in GtoPdb v.2021.3

Opioid and opioid-like receptors are activated by a variety of endogenous peptides including [Met]enkephalin (met), [Leu]enkephalin (leu), β-endorphin (β-end), α-neodynorphin, dynorphin A (dynA), B (dynB), big (Big dyn), nociceptin/orphanin FQ (N/OFQ); endomorphin-1 endomorphin-2 also potential peptides. The Greek letter nomenclature for the opioid receptors, μ, δ κ, is well established, NC-IUPHAR considers this appropriate, along with symbols spelled out (mu, delta, kappa), acronyms, MOP, DOP, KOP. [121, 100, 91]. human N/OFQ receptor, NOP, considered 'opioid-related' rather than because, while it exhibits high degree structural homology conventional [294], displays distinct pharmacology. Currently there numerous clinically used drugs, such as morphine many other analgesics, antagonists naloxone, however only μ receptor.