PMID: 9523574Apr 2, 1998Paper

Endomorphin-stimulated [35S]GTPgammaS binding in rat brain: evidence for partial agonist activity at mu-opioid receptors

Journal of Neurochemistry
L J SimD E Selley

Abstract

Endomorphin-1 is a peptide whose binding selectivity suggests a role as an endogenous ligand at mu-opioid receptors. In the present study, the effect of endomorphin-1 on mu receptor-coupled G proteins was compared with that of the mu agonist DAMGO by using agonist-stimulated [35S]GTPgammaS binding in rat brain. [35S]GTPgammaS autoradiography revealed a similar localization of endomorphin-1- and DAMGO-stimulated [35S]GTPgammaS binding in areas including thalamus, caudate-putamen, amygdala, periaqueductal gray, parabrachial nucleus, and nucleus tractus solitarius. Naloxone blocked endomorphin-1-stimulated labeling in all regions examined. Although the distribution of endomorphin-1-stimulated [35S]GTPgammaS binding resembled that of DAMGO, the magnitude of endomorphin-1-stimulated binding was significantly lower than that produced by DAMGO. Concentration-effect curves of endomorphin-1 and DAMGO in thalamic membranes confirmed that endomorphin-1 produced only 70% of DAMGO-stimulated [35S]GTPgammaS binding. Differences in maximal stimulation of [35S]GTPgammaS binding between DAMGO and endomorphin-1 were magnified by increasing GDP concentrations, and saturation analysis of net endomorphin-1-stimulated [35S]GTPgammaS binding revealed...Continue Reading

Citations

May 22, 2010·ChemMedChem·Attila KeresztesGéza Tóth
Apr 20, 2005·Journal of Neurochemistry·Steven R ChildersJames C Eisenach
May 4, 2012·Molecular Pharmacology·Guadalupe RiveroEamonn Kelly
May 8, 2013·British Journal of Pharmacology·E Kelly
Oct 24, 1998·Biochemical and Biophysical Research Communications·M SpeteaA Borsodi
Feb 26, 2000·European Journal of Pharmacology·L J Sim-SelleyD E Selley
Jul 20, 2002·European Journal of Pharmacology·María José García-BarradoJulio Moratinos
Feb 21, 2006·Brain Research Reviews·Gyongyi Horvath, Gabriella Kekesi
May 9, 2006·Biochemical and Biophysical Research Communications·Jakub FichnaAnna Janecka
Sep 22, 2012·Journal of Medicinal Chemistry·Rossella De MarcoLuca Gentilucci
Nov 9, 2007·Peptides·Weihong Pan, Abba J Kastin

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