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Effect of chronic D-Ala,2 D-Leu5-enkephalin or pertussis toxin treatment on the high-affinity state of delta opioid receptor in neuroblastoma x glioma NG108-15 hybrid cells.
J Pharmacol Exp Ther. 1991 Feb; 256(2):710-6.JP

Abstract

Chronic treatment of neuroblastoma x glioma NG108-15 hybrid cells with the opioid agonist D-Ala,2 D-Leu5-enkephalin (DADLE) induces a homologous desensitization of the delta opioid receptors present in these cells. Since the Kd value of the delta opioid receptor's high-affinity state reflects the potency of the agonist, we examined the effect of receptor desensitization in NG108-15 cells on the percentage of receptor in the high-affinity state. When NG108-15 hybrid cells were treated with 10 or 100 nM DADLE for 4 hr at 24 degrees C, loss of DADLE's ability to inhibit adenylate cyclase was observed. However, when competition binding experiments were carried out with P2P3 membranes isolated from the delta opioid-desensitized hybrid cells, it was determined that 41.7 +/- 3.4% of the total binding sites remained in the high-affinity state, with no apparent alteration in the Kd value of either high- or low-affinity states. Similarly, when NG108-15 cells were treated with 100 ng/ml of pertussis toxin for 3 hr at 37 degrees C, 39.9 +/- 3.6% of the binding sites remained in the high-affinity state. This reduction in the percentage of receptor in high-affinity state was agonist specific, for chronic treatment of hybrid cells with levorphanol, a partial agonist, or the antagonist naloxone did not alter the percentage of opioid receptors in the high-affinity state. Furthermore, the delta opioid receptors remaining in the high-affinity state after chronic DADLE treatment were still sensitive to both Na+ and guanyldylimidodiphosphate, indicating that opioid ligand binding remained coupled to the G-proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

Department of Pharmacology, University of Minnesota, Minneapolis.No affiliation info availableNo affiliation info available

Pub Type(s)

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

Language

eng

PubMed ID

1847209

Citation

Law, P Y., et al. "Effect of Chronic D-Ala,2 D-Leu5-enkephalin or Pertussis Toxin Treatment On the High-affinity State of Delta Opioid Receptor in Neuroblastoma X Glioma NG108-15 Hybrid Cells." The Journal of Pharmacology and Experimental Therapeutics, vol. 256, no. 2, 1991, pp. 710-6.
Law PY, Hom DS, Loh HH. Effect of chronic D-Ala,2 D-Leu5-enkephalin or pertussis toxin treatment on the high-affinity state of delta opioid receptor in neuroblastoma x glioma NG108-15 hybrid cells. J Pharmacol Exp Ther. 1991;256(2):710-6.
Law, P. Y., Hom, D. S., & Loh, H. H. (1991). Effect of chronic D-Ala,2 D-Leu5-enkephalin or pertussis toxin treatment on the high-affinity state of delta opioid receptor in neuroblastoma x glioma NG108-15 hybrid cells. The Journal of Pharmacology and Experimental Therapeutics, 256(2), 710-6.
Law PY, Hom DS, Loh HH. Effect of Chronic D-Ala,2 D-Leu5-enkephalin or Pertussis Toxin Treatment On the High-affinity State of Delta Opioid Receptor in Neuroblastoma X Glioma NG108-15 Hybrid Cells. J Pharmacol Exp Ther. 1991;256(2):710-6. PubMed PMID: 1847209.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effect of chronic D-Ala,2 D-Leu5-enkephalin or pertussis toxin treatment on the high-affinity state of delta opioid receptor in neuroblastoma x glioma NG108-15 hybrid cells. AU - Law,P Y, AU - Hom,D S, AU - Loh,H H, PY - 1991/2/1/pubmed PY - 1991/2/1/medline PY - 1991/2/1/entrez SP - 710 EP - 6 JF - The Journal of pharmacology and experimental therapeutics JO - J Pharmacol Exp Ther VL - 256 IS - 2 N2 - Chronic treatment of neuroblastoma x glioma NG108-15 hybrid cells with the opioid agonist D-Ala,2 D-Leu5-enkephalin (DADLE) induces a homologous desensitization of the delta opioid receptors present in these cells. Since the Kd value of the delta opioid receptor's high-affinity state reflects the potency of the agonist, we examined the effect of receptor desensitization in NG108-15 cells on the percentage of receptor in the high-affinity state. When NG108-15 hybrid cells were treated with 10 or 100 nM DADLE for 4 hr at 24 degrees C, loss of DADLE's ability to inhibit adenylate cyclase was observed. However, when competition binding experiments were carried out with P2P3 membranes isolated from the delta opioid-desensitized hybrid cells, it was determined that 41.7 +/- 3.4% of the total binding sites remained in the high-affinity state, with no apparent alteration in the Kd value of either high- or low-affinity states. Similarly, when NG108-15 cells were treated with 100 ng/ml of pertussis toxin for 3 hr at 37 degrees C, 39.9 +/- 3.6% of the binding sites remained in the high-affinity state. This reduction in the percentage of receptor in high-affinity state was agonist specific, for chronic treatment of hybrid cells with levorphanol, a partial agonist, or the antagonist naloxone did not alter the percentage of opioid receptors in the high-affinity state. Furthermore, the delta opioid receptors remaining in the high-affinity state after chronic DADLE treatment were still sensitive to both Na+ and guanyldylimidodiphosphate, indicating that opioid ligand binding remained coupled to the G-proteins.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0022-3565 UR - https://www.unboundmedicine.com/medline/citation/1847209/Effect_of_chronic_D_Ala2_D_Leu5_enkephalin_or_pertussis_toxin_treatment_on_the_high_affinity_state_of_delta_opioid_receptor_in_neuroblastoma_x_glioma_NG108_15_hybrid_cells_ L2 - https://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=1847209 DB - PRIME DP - Unbound Medicine ER -