Comparison of G-protein activation in the brain by μ-, δ-, and κ-opioid receptor agonists in μ-opioid receptor knockout mice

Younjoo Park, Tangeng Ma, Sachiko Tanaka, Choon Gon Jang, Horace H. Loh, Kwang Ho Ko, Ing Kang Ho

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Mice lacking the μ-opioid receptor gene have been developed by a gene knockout procedure. In this study, the activity of opioid receptor coupled G-proteins was examined to investigate whether there is a change in the extent of coupling for μ-, δ-, and κ-opioid receptors in μ-opioid receptor knockout mice. Selective agonists of μ- (DAMGO), δ- (DPDPE), and κ- (U-69,593) opioid receptors stimulated [35S]GTPγS binding in the caudate putamen and cortex of wild-type mice. In contrast, only U-69,593 stimulated [35S]GTPγS binding in these regions of μ-opioid receptor knockout mice. These results confirmed the absence of G-protein activation by a μ-opioid receptor agonist in μ-opioid receptor knockout mice, and demonstrated that coupling of the κ-opioid receptor to G-proteins is preserved in these mice. However, G-protein activation by the δ-opioid receptor agonist, DPDPE, was reduced in the μ-opioid receptor knockout mice, at least in the brain regions studied using autoradiography. Copyright (C) 2000 Elsevier Science Inc.

Original languageEnglish (US)
Pages (from-to)297-302
Number of pages6
JournalBrain Research Bulletin
Volume52
Issue number4
DOIs
StatePublished - Jul 1 2000

Keywords

  • G-Protein coupling
  • δ-
  • κ-Opioid receptor
  • μ-
  • μ-Opioid receptor knockout mice

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