Tramadol, M1 metabolite and enantiomer affinities for cloned human opioid receptors expressed in transfected HN9.10 neuroblastoma cells

Josephine Lai, Shou Wu Ma, Frank Porreca, Robert B. Raffa

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

Tramadol hydrochloride is a centrally acting synthetic analgesic in widespread clinical use. Despite different degrees of opioid-like characteristics in preclinical tests, it is characterized by lack of full naloxone reversibility or naloxone-precipitated withdrawal in humans. To investigate this apparent discrepancy, the present study measured the affinity of tramadol (and its enantiomers) and an active O-desmethyl metabolite (M1) (and its enantiomers) to cloned human opioid receptors of the μ, δ and κ type stably expressed in HN9.10 neuroblastoma cells. At μ sites, the K(i) values for tramadol, its (+) and (-) enantiomers, M1, and its (+) and (-) enantiomers were 17,000, 15,700, 28,800, 3190, 153 and 9680 nM, respectively, compared to 7.1 nM for morphine. These results are consistent with the suggestion of a non-opioid contribution to the clinical profile of tramadol.

Original languageEnglish (US)
Pages (from-to)369-372
Number of pages4
JournalEuropean Journal of Pharmacology
Volume316
Issue number2-3
DOIs
StatePublished - Dec 5 1996

Keywords

  • Analgesia
  • Cloned human receptor
  • Opioid receptor type
  • Tramadol

ASJC Scopus subject areas

  • Pharmacology

Fingerprint Dive into the research topics of 'Tramadol, M1 metabolite and enantiomer affinities for cloned human opioid receptors expressed in transfected HN9.10 neuroblastoma cells'. Together they form a unique fingerprint.

  • Cite this