Morphine-6-glucuronide, a potent mu agonist.
The 3- and the 6-glucuronides of morphine have been examined in binding studies and in vivo. The 3-glucuronide had poor affinity in all binding studies whereas the 6-glucuronide potently labeled mu, but not delta or kappa receptors with affinities similar to morphine. Microinjections of the 3-glucuronide directly into the periaqueductal gray were without effect. The 6-glucuronide, on the other hand, was up to 20-fold more potent than morphine following microinjections in the same region. High doses of the 6-glucuronide produced profound seizure activity. All 6-glucuronide actions were sensitive to the opiate antagonist naloxone.
Pasternak
G W
GW
Cotzias Laboratory of Neuro-Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY.
Bodnar
R J
RJ
Clark
J A
JA
Inturrisi
C E
CE
D000818:Animals; D001711:Biotransformation; D008297:Male; D008845:Microinjections; D009020:Morphine / Q000378:metabolism / Q000494:pharmacology; D009022:Morphine Derivatives / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000378:metabolism*; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu
D009022:Morphine Derivatives; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; C035349:morphine-6-glucuronide; D009020:Morphine; C018108:morphine-3-glucuronide