Selective modulation of morphine antinociception, but not development of tolerance, by δ receptor agonists

Jiang Qi, Henry I. Mosberg, Frank Porreca

Research output: Contribution to journalArticle

40 Scopus citations


Co-administration of δ opioid agonists at doses which do not produce measurable antinociception were demonstrated to produce an increase in the antinociceptive potency of morphine in the mouse tail-flick test. In contrast, co-administration of equi-antinociceptive combinations of a δ agonist plus morphine for three days resulted in the development of less tolerance to morphine antinociceptive actions. The data indicate that while acute antinociceptive effects of opioid μ agonists are modulated by δ agonists, the development of antinociceptive tolerance is not.

Original languageEnglish (US)
Pages (from-to)137-141
Number of pages5
JournalEuropean Journal of Pharmacology
Issue number1
StatePublished - Sep 4 1990



  • Antinociception
  • Morphine
  • Tolerance
  • δ-Opioid receptor agonists

ASJC Scopus subject areas

  • Pharmacology

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