Characterization of kappa opioid receptor mediated, dynorphin-stimulated [35S]GTPγS binding in mouse striatum for the evaluation of selective KOR ligands in an endogenous setting

Lei Zhou, Edward L. Stahl, Kimberly M. Lovell, Kevin J. Frankowski, Thomas E. Prisinzano, Jeffrey Aubé, Laura M. Bohn

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Abstract Differential modulation of kappa opioid receptor (KOR) signaling has been a proposed strategy for developing therapies for drug addiction and depression by either activating or blocking this receptor. Hence, there have been significant efforts to generate ligands with diverse pharmacological properties including partial agonists, antagonists, allosteric modulators as well as ligands that selectively activate some pathways while not engaging others (biased agonists). It is becoming increasingly evident that G protein coupled receptor signaling events are context dependent and that what may occur in cell based assays may not be fully indicative of signaling events that occur in the naturally occurring environment. As new ligands are developed, it is important to assess their signaling capacity in relevant endogenous systems in comparison to the performance of endogenous agonists. Since KOR is considered the cognate receptor for dynorphin peptides we have evaluated the selectivity profiles of dynorphin peptides in wild-type (WT), KOR knockout (KOR-KO), and mu opioid receptor knockout (MOR-KO) mice using [35S]GTPγS binding assay in striatal membrane preparations. We find that while the small molecule KOR agonist U69,593, is very selective for KOR, dynorphin peptides promiscuously stimulate G protein signaling in striatum. Furthermore, our studies demonstrate that norBNI and 5′GNTI are highly nonselective antagonists as they maintain full potency and efficacy against dynorphin signaling in the absence of KOR. Characterization of a new KOR antagonist, which may be more selective than NorBNI and 5′GNTI, is presented using this approach.

Original languageEnglish
Article number5907
Pages (from-to)131-141
Number of pages11
JournalNeuropharmacology
Volume99
DOIs
StatePublished - Aug 3 2015

Bibliographical note

Publisher Copyright:
© 2015 Elsevier Ltd.

Funding

We thank Huiyong Ma of KU for his help in chemical synthesis efforts. This work was funded by NIDA grant R01DA031927 to L. Bohn and J. Aubé.

FundersFunder number
National Institute on Drug AbuseR01DA031927

    Keywords

    • Drug discovery
    • Dynorphin
    • KOR antagonist
    • Kappa opioid receptor
    • Mouse striatum
    • Selectivity
    • [S]GTPγS binding

    ASJC Scopus subject areas

    • Pharmacology
    • Cellular and Molecular Neuroscience

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