Spinal and supraspinal opioid analgesia in the mouse: the role of subpopulations of opioid binding sites

Geoffrey S.F. Ling, Gavril W. Pasternak

Research output: Contribution to journalArticlepeer-review

Abstract

The selective in vivo blockade of high affinity (mu1) opioid binding sites in mice by naloxazone reduced the analgesic potency of opiates and opioid peptides, evidenced by a shift of their analgesic ED50 values. However, the extent of these shifts varied significantly between a series of opioid drugs, ranging from 12-fold for morphine to 4-fold for d-Ala2-d-Leu5-enkephalin. These findings suggested that analgesia in naloxazone-treated animals is mediated through a different subpopulation of receptors than in normal controls. Correlating these analgesic shifts for a series of opioids with their affinity for different [3H]opioid binding sites suggested an analgesic role for delta sites. Additional studies in mice with spinal transections suggested that mu1 analgesia was primarily supraspinal.

Original languageEnglish (US)
Pages (from-to)152-156
Number of pages5
JournalBrain research
Volume271
Issue number1
DOIs
StatePublished - Jul 18 1983

Keywords

  • analgesia
  • delta receptor
  • enkephalin
  • mu receptor
  • naloxazone
  • opiate

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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