Codeine and 6-acetylcodeine analgesia in mice

Steven Milo, Michael Ansonoff, Michael King, Grace C. Rossi, Amy Zuckerman, John Pintar, Gavril W. Pasternak

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


1. Acetylation of morphine at the 6-position changes its pharmacology. To see if similar changes are seen with codeine, we examined the analgesic actions of codeine and 6-acetylcodeine. 2. Like codeine, 6-acetylcodeine is an effective analgesic systemically, supraspinally and spinally, with a potency approximately a third that of codeine. 3. The sensitivity of 6-acetylcodeine analgesia to the mu-selective antagonists β-FNA and naloxonazine confirmed its classification as a mu opioid. However, it differed from the other mu analgesics in other paradigms. 4. Antisense mapping revealed the sensitivity of 6-acetylcodeine to probes targeting exons 1 and 2 of the mu opioid receptor gene (Oprm), a profile distinct from either codeine or morphine. Although heroin analgesia also is sensitive to antisense targeting exons 1 and 2, heroin analgesia also is sensitive to the antagonist 3-O-methylnaltrexone, while 6-acetylcodeine analgesia is not. 5. Thus, 6-acetylcodeine is an effective mu opioid analgesic with a distinct pharmacological profile.

Original languageEnglish (US)
Pages (from-to)1011-1019
Number of pages9
JournalCellular and Molecular Neurobiology
Issue number4-6
StatePublished - Jul 2006

All Science Journal Classification (ASJC) codes

  • Cellular and Molecular Neuroscience
  • Cell Biology


  • 6-acetylcodeine
  • Analgesia
  • Antisense
  • Codeine
  • Heroin
  • MOR-1
  • Morphine
  • Mu opioid receptor
  • Opioid


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