Effects of beta-funaltrexamine (beta-FNA) on morphine dependence in rats and monkeys.
The opioid mu receptor antagonist beta-funaltrexamine (beta-FNA) blocked the development of physical dependence in rats when infused simultaneously with morphine for 6 days. In addition, beta-FNA given s.c. 24 h prior to the initiation and on day 3 of a 6 day period of morphine infusion in rats reduced the development of physical dependence in a dose-dependent manner. In morphine-dependent rhesus monkeys, beta-FNA precipitated a prompt and long-lasting withdrawal, which was not reversed within 30 h by subsequent injections of morphine. In contrast, naloxone-induced withdrawal lasted approximately 90 min. These results provide further evidence that beta-FNA is a long-acting antagonist of the opioid mu receptor, and that this receptor has a major role in the development of morphine-induced physical dependence.
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D008253:Macaca mulatta; D008297:Male; D009021:Morphine Dependence / Q000517:prevention & control*; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013375:Substance Withdrawal Syndrome / Q000517:prevention & control; D013997:Time Factors
D009292:Narcotic Antagonists; D009271:Naltrexone; C024524:beta-funaltrexamine