The apparent affinity of morphine-3-glucuronide at mu1-opioid receptors results from morphine contamination: demonstration using HPLC and radioligand binding. 1995

S E Bartlett, and M T Smith
Department of Pharmacy, University of Queensland, Brisbane, Australia.

Equilibrium binding studies in sheep thalamic homogenates indicated that morphine-3-glucuronide (M3G) had an apparent affinity for mu1-opioid binding sites (IC50 = 178 +/- 40 nM, Ki = 116 +/- 25 nM, mean +/- s.e.m., n = 4) similar to that reported by Pasternak and co-workers (1). However, when the chemical purity of M3G was investigated using high-performance-liquid-chromatography (HPLC) with electrochemical detection, it was found to be contaminated with 0.5% (molar basis) of morphine. Reduction of the morphine contamination of M3G to 0.08% resulted in a 7.2-fold decrease in apparent binding affinity (IC50 = 1279 +/- 287 nM, Ki = 766 +/- 30 nM, mean +/- s.e.m., n = 4), indicating that the small percentage of morphine present in the M3G raw material drug is the likely explanation for M3G's apparent binding to mu1-opioid receptors.

UI MeSH Term Description Entries
D009020 Morphine The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle. Morphine Sulfate,Duramorph,MS Contin,Morphia,Morphine Chloride,Morphine Sulfate (2:1), Anhydrous,Morphine Sulfate (2:1), Pentahydrate,Oramorph SR,SDZ 202-250,SDZ202-250,Chloride, Morphine,Contin, MS,SDZ 202 250,SDZ 202250,SDZ202 250,SDZ202250,Sulfate, Morphine
D009022 Morphine Derivatives Analogs or derivatives of morphine. Morphines
D011869 Radioligand Assay Quantitative determination of receptor (binding) proteins in body fluids or tissue using radioactively labeled binding reagents (e.g., antibodies, intracellular receptors, plasma binders). Protein-Binding Radioassay,Radioreceptor Assay,Assay, Radioligand,Assay, Radioreceptor,Assays, Radioligand,Assays, Radioreceptor,Protein Binding Radioassay,Protein-Binding Radioassays,Radioassay, Protein-Binding,Radioassays, Protein-Binding,Radioligand Assays,Radioreceptor Assays
D002851 Chromatography, High Pressure Liquid Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed. Chromatography, High Performance Liquid,Chromatography, High Speed Liquid,Chromatography, Liquid, High Pressure,HPLC,High Performance Liquid Chromatography,High-Performance Liquid Chromatography,UPLC,Ultra Performance Liquid Chromatography,Chromatography, High-Performance Liquid,High-Performance Liquid Chromatographies,Liquid Chromatography, High-Performance
D003342 Corpus Striatum Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE. Lenticular Nucleus,Lentiform Nucleus,Lentiform Nuclei,Nucleus Lentiformis,Lentiformis, Nucleus,Nuclei, Lentiform,Nucleus, Lenticular,Nucleus, Lentiform,Striatum, Corpus
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012756 Sheep Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS. Ovis,Sheep, Dall,Dall Sheep,Ovis dalli
D013788 Thalamus Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain. Thalamencephalon,Thalamencephalons
D017450 Receptors, Opioid, mu A class of opioid receptors recognized by its pharmacological profile. Mu opioid receptors bind, in decreasing order of affinity, endorphins, dynorphins, met-enkephalin, and leu-enkephalin. They have also been shown to be molecular receptors for morphine. Morphine Receptors,Opioid Receptors, mu,Receptors, Morphine,Receptors, mu,Receptors, mu Opioid,mu Receptors,Morphine Receptor,mu Opioid Receptor,mu Receptor,Opioid Receptor, mu,Receptor, Morphine,Receptor, mu,Receptor, mu Opioid,mu Opioid Receptors

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