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Characterization of opioid agonist efficacy in a C6 glioma cell line expressing the mu opioid receptor.
J Pharmacol Exp Ther. 1996 Sep; 278(3):1121-7.JP

Abstract

In C6 glioma cells stably expressing a homogeneous population of the cloned rat mu opioid receptor, the binding affinities of opioid agonists and subsequent activation of G protein were examined. Opioid receptor number in membranes of these cells was high (10-30 pmol/mg protein [3H]diprenorphine binding sites). Opioids were found to bind to the receptor with high affinity [Tyr-D-Ala-Gly-(Me)Phe-Gly-ol (DAMGO) 0.23 nM; sufentanil 0.034 nM; morphine 0.16 nM]. Activation of G protein by opioid agonists was examined by measuring the stimulation of guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTP gamma S) binding. Sufentanil increased [35S]GTP gamma S binding by 326% with an EC50 value of 2.39 nM. Agonist stimulation of [35S]GTP gamma S binding was stereoselective, naltrexone-reversible, and pertussis toxin-sensitive. The "intrinsic activity" of opioids at the mu receptor was reflected by the magnitude of agonist-mediated activation of G protein. The rank order of the stimulation of [35S]GTP gamma S binding was etonitazene = sufentanil = DAMGO = PLO17 = fentanyl > morphine > profadol > meperidine > butorphanol = nalbuphine = pentazocine > cyclazocine = nalorphine > levallorphan > naltrexone. High affinity binding of ligands to the mu opioid receptor was reduced by the addition of sodium and guanosine diphosphate at concentrations used in the [35S]GTP gamma S binding assay. Ligand affinity was reduced in a manner correlating with "intrinsic activity". DAMGO, 1229-fold, nalbuphine 35-fold, naltrexone, 3-fold. The results presented show that the stable expression of the rat mu opioid receptor in C6 cells provides an effective tool to examine opioid receptor signal transduction mechanisms and evaluate the activity of novel opioids at the mu receptor.

Authors+Show Affiliations

Department of Pharmacology, University of Michigan, Ann Arbor, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

8819494

Citation

Emmerson, P J., et al. "Characterization of Opioid Agonist Efficacy in a C6 Glioma Cell Line Expressing the Mu Opioid Receptor." The Journal of Pharmacology and Experimental Therapeutics, vol. 278, no. 3, 1996, pp. 1121-7.
Emmerson PJ, Clark MJ, Mansour A, et al. Characterization of opioid agonist efficacy in a C6 glioma cell line expressing the mu opioid receptor. J Pharmacol Exp Ther. 1996;278(3):1121-7.
Emmerson, P. J., Clark, M. J., Mansour, A., Akil, H., Woods, J. H., & Medzihradsky, F. (1996). Characterization of opioid agonist efficacy in a C6 glioma cell line expressing the mu opioid receptor. The Journal of Pharmacology and Experimental Therapeutics, 278(3), 1121-7.
Emmerson PJ, et al. Characterization of Opioid Agonist Efficacy in a C6 Glioma Cell Line Expressing the Mu Opioid Receptor. J Pharmacol Exp Ther. 1996;278(3):1121-7. PubMed PMID: 8819494.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of opioid agonist efficacy in a C6 glioma cell line expressing the mu opioid receptor. AU - Emmerson,P J, AU - Clark,M J, AU - Mansour,A, AU - Akil,H, AU - Woods,J H, AU - Medzihradsky,F, PY - 1996/9/1/pubmed PY - 1996/9/1/medline PY - 1996/9/1/entrez SP - 1121 EP - 7 JF - The Journal of pharmacology and experimental therapeutics JO - J Pharmacol Exp Ther VL - 278 IS - 3 N2 - In C6 glioma cells stably expressing a homogeneous population of the cloned rat mu opioid receptor, the binding affinities of opioid agonists and subsequent activation of G protein were examined. Opioid receptor number in membranes of these cells was high (10-30 pmol/mg protein [3H]diprenorphine binding sites). Opioids were found to bind to the receptor with high affinity [Tyr-D-Ala-Gly-(Me)Phe-Gly-ol (DAMGO) 0.23 nM; sufentanil 0.034 nM; morphine 0.16 nM]. Activation of G protein by opioid agonists was examined by measuring the stimulation of guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTP gamma S) binding. Sufentanil increased [35S]GTP gamma S binding by 326% with an EC50 value of 2.39 nM. Agonist stimulation of [35S]GTP gamma S binding was stereoselective, naltrexone-reversible, and pertussis toxin-sensitive. The "intrinsic activity" of opioids at the mu receptor was reflected by the magnitude of agonist-mediated activation of G protein. The rank order of the stimulation of [35S]GTP gamma S binding was etonitazene = sufentanil = DAMGO = PLO17 = fentanyl > morphine > profadol > meperidine > butorphanol = nalbuphine = pentazocine > cyclazocine = nalorphine > levallorphan > naltrexone. High affinity binding of ligands to the mu opioid receptor was reduced by the addition of sodium and guanosine diphosphate at concentrations used in the [35S]GTP gamma S binding assay. Ligand affinity was reduced in a manner correlating with "intrinsic activity". DAMGO, 1229-fold, nalbuphine 35-fold, naltrexone, 3-fold. The results presented show that the stable expression of the rat mu opioid receptor in C6 cells provides an effective tool to examine opioid receptor signal transduction mechanisms and evaluate the activity of novel opioids at the mu receptor. SN - 0022-3565 UR - https://www.unboundmedicine.com/medline/citation/8819494/Characterization_of_opioid_agonist_efficacy_in_a_C6_glioma_cell_line_expressing_the_mu_opioid_receptor_ L2 - https://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=8819494 DB - PRIME DP - Unbound Medicine ER -