Cyprenorphine (M285), N-cyclo-propylmethyl-6,14-endoetheno-7α-(1-hydroxy-1-methylethyl)-6,7,8,14-tetrahydronororipavine, is an opioid drug. It is related to more well-known opioids such as buprenorphine, which is used as an analgesic and for the treatment of opioid addiction, and diprenorphine, which is used as an antidote to reverse the effects of other opioids. It is roughly 35 times as strong as nalorphine.[1]
Cyprenorphine is a powerful antagonist of opioid receptors[2] and a highly potent specific antagonist.[3] It blocks the binding of morphine and etorphine to these receptors.[3]
Cyprenorphine has mixed agonist–antagonist effects at opioid receptors, like those of buprenorphine. However the effects of cyprenorphine are somewhat different, as it produces pronounced dysphoric and hallucinogenic effects which limit its potential use as an analgesic.[4][5]
Cyprenorphine also has been shown to suppress the intake of sweet solution[2] but doesn't suppress the increase in food consumption that is produced by the alpha-2-adrenoceptor antagonist idazoxan. Idazoxan may lead to the release of endogenous opioid peptides and increase food intake, this effect is attenuated by (-)-naloxone but not by the mu/delta-antagonist cyprenorphine.[6]
^Dobbs HE (April 1968). "Effect of cyprenorphine (M285), a morphine antagonist, on the distribution and excretion of etorphine (M99), a potent morphine-like drug". The Journal of Pharmacology and Experimental Therapeutics. 160 (2): 407–414. PMID5647307.
^ abCalcagnetti DJ, Calcagnetti RL, Fanselow MS (January 1990). "Centrally administered opioid antagonists, nor-binaltorphimine, 16-methyl cyprenorphine and MR2266, suppress intake of a sweet solution". Pharmacology, Biochemistry, and Behavior. 35 (1): 69–73. doi:10.1016/0091-3057(90)90206-w. PMID2315372. S2CID12321010.