Beta-Funaltrexamine Explained

β-Funaltrexamine (β-FNA) is an irreversible (covalently bonding) opioid antagonist that was used to create the first crystal structure of the μ-opioid receptor.^[1] Chemically, it is a naltrexone derivative with a methyl-fumaramide group in the 6-position. In addition to its μ-opioid receptor irreversible antagonism, β-FNA is an agonist of the κ-opioid receptor and produces κ-opioid-receptor-mediated analgesic effects in animals.^{[2] [3]} This has limited its usefulness and contributed to the development of methocinnamox as a functionally irreversible antagonist of the μ-opioid receptor with no agonistic actions.

See also

• β-Fuoxymorphamine

Notes and References

1. Manglik A, Kruse AC, Kobilka TS, Thian FS, Mathiesen JM, Sunahara RK, Pardo L, Weis WI, Kobilka BK, Granier S . 6 . Crystal structure of the µ-opioid receptor bound to a morphinan antagonist . Nature . 485 . 7398 . 321–6 . March 2012 . 22437502 . 3523197 . 10.1038/nature10954 . 2012Natur.485..321M .
2. Broadbear JH, Sumpter TL, Burke TF, Husbands SM, Lewis JW, Woods JH, Traynor JR . Methocinnamox is a potent, long-lasting, and selective antagonist of morphine-mediated antinociception in the mouse: comparison with clocinnamox, beta-funaltrexamine, and beta-chlornaltrexamine . J Pharmacol Exp Ther . 294 . 3 . 933–940 . September 2000 . 10945843 .
3. Qi JA, Heyman JS, Sheldon RJ, Koslo RJ, Porreca F . Mu antagonist and kappa agonist properties of beta-funaltrexamine (beta-FNA) in vivo: long-lasting spinal analgesia in mice . J Pharmacol Exp Ther . 252 . 3 . 1006–1011 . March 1990 . 2156986 .