3-Methoxynaltrexone, a selective heroin/morphine-6β-glucuronide antagonist
Recent work has suggested that heroin and morphine-6β-glucuronide (M6G) both act through a novel mu opioid receptor subtype distinct from those mediating morphine's actions. This very high affinity 3H-M6G site is selectively competed by 3-methoxynaltrexone. In vivo, 3-methoxynaltrexone (2.5 ng,...
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Published in | FEBS letters Vol. 412; no. 1; pp. 35 - 38 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
21.07.1997
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Subjects | |
Online Access | Get full text |
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Summary: | Recent work has suggested that heroin and morphine-6β-glucuronide (M6G) both act through a novel mu opioid receptor subtype distinct from those mediating morphine's actions. This very high affinity
3H-M6G site is selectively competed by 3-methoxynaltrexone. In vivo, 3-methoxynaltrexone (2.5 ng, i.c.v.) selectively antagonizes the analgesic actions of heroin and M6G without interfering with mu (morphine and [
d-Ala
2,MePhe
4,Gly(ol)
5]enkephalin), delta ([
d-Pen
2,
d-Pen
5]enkephalin), kappa
1 (U50,488H) or kappa
3 (naloxone benzoylhydrazone) analgesia. In dose–response studies, 3-methoxynaltrexone (2.5 ng, i.c.v.) significantly shifted the ED
50 values for heroin and its active metabolite, 6-acetylmorphine, without affecting the morphine curve. These results indicate that 3-methoxynaltrexone selectively blocks a novel
3H-M6G binding site which is responsible for the analgesic actions of heroin and M6G. This ability to selectively antagonize heroin actions opens new possibilities in the development of therapeutics for the treatment of opioid abuse. |
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ISSN: | 0014-5793 1873-3468 |
DOI: | 10.1016/S0014-5793(97)00710-2 |