Separation of morphine analgesia from physical dependence.

Abstract

Intravenous infusion of morphine sulfate in rats for 24 hours produced marked opioid dependence, manifested by a series of well-documented signs appearing after injection of the opiate antagonist naloxone. Treatment of rats with naloxonazine significantly reduced the analgesia associated with the morphine infusions for more than 24 hours. Furthermore, 14 of 16 withdrawal signs observed in naloxonazine-treated rats were virtually identical to those in rats that received morphine alone. These results raise the possibility that different receptor mechanisms mediate morphine analgesia and many of the withdrawal signs associated with morphine dependence.

• Authors: G S Ling, J M MacLeod, S Lee, S H Lockhart, G W Pasternak
• Journal: Science (New York, N.Y.) (Science) Vol. 226 Issue 4673 Pg. 462-4 (Oct 26 1984) ISSN: 0036-8075 [Print] United States
• PMID: 6541807 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Naloxone
• Morphine
• naloxonazine

Topics

• Analgesia
• Animals
• Humans
• Male
• Morphine (pharmacology)
• Naloxone (analogs & derivatives, pharmacology)
• Rats
• Rats, Inbred Strains
• Substance Withdrawal Syndrome
• Substance-Related Disorders