Biomaterial Database

Opioid receptor desensitization in NG 108-15 cells. Differential effects of a full and a partial agonist on the opioid-dependent GTPase. 1987

L Vachon, and T Costa, and A Herz

Opioid-receptor binding and the opioid-mediated stimulation of low Km GTPase and inhibition of adenylate cyclase were studied in membranes derived from NG 108-15 cells pretreated with either the opioid peptide [D-Ala2, D-Leu5]enkephalin (DADLE) or morphine. Pretreatment with DADLE resulted in a concentration-dependent loss of responsiveness of GTPase to the peptide; this effect was entirely accounted for by a reduction in the maximal stimulation produced acutely by DADLE, without changes in the EC50 of the peptide, indicating a non-competitive type of desensitization. The degree of desensitization of GTPase was similar after one and 24 hr of pretreatment with DADLE, indicating that the process occurs rapidly. In contrast, morphine, which was 70-80% as potent as DADLE in stimulating GTPase and inhibiting adenylate cyclase in acute conditions, induced only a minimal desensitization of the opioid-GTPase system and, in contrast to DADLE, did not desensitize adenylate cyclase. Pretreatment with DADLE for one hour led to a decrease in opioid receptor density which was quantitatively similar to the degree of desensitization of GTPase: both these effects of DADLE were antagonized to a similar extent when morphine was also present in the pretreatment. Thus, desensitization of the opioid-stimulated GTPase appears to be correlated with down-regulation of the opioid receptor. Moreover, these findings suggest that partial agonists cannot induce this process.

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
D009447	Neuroblastoma	A common neoplasm of early childhood arising from neural crest cells in the sympathetic nervous system, and characterized by diverse clinical behavior, ranging from spontaneous remission to rapid metastatic progression and death. This tumor is the most common intraabdominal malignancy of childhood, but it may also arise from thorax, neck, or rarely occur in the central nervous system. Histologic features include uniform round cells with hyperchromatic nuclei arranged in nests and separated by fibrovascular septa. Neuroblastomas may be associated with the opsoclonus-myoclonus syndrome. (From DeVita et al., Cancer: Principles and Practice of Oncology, 5th ed, pp2099-2101; Curr Opin Oncol 1998 Jan;10(1):43-51)	Neuroblastomas
D010744	Phosphoric Monoester Hydrolases	A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate.	Phosphatase,Phosphatases,Phosphohydrolase,Phosphohydrolases,Phosphomonoesterase,Phosphomonoesterases,Phosphoric Monoester Hydrolase,Hydrolase, Phosphoric Monoester,Hydrolases, Phosphoric Monoester,Monoester Hydrolase, Phosphoric
D011957	Receptors, Opioid	Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.	Endorphin Receptors,Enkephalin Receptors,Narcotic Receptors,Opioid Receptors,Receptors, Endorphin,Receptors, Enkephalin,Receptors, Narcotic,Receptors, Opiate,Endorphin Receptor,Enkephalin Receptor,Normorphine Receptors,Opiate Receptor,Opiate Receptors,Opioid Receptor,Receptors, Normorphine,Receptors, beta-Endorphin,beta-Endorphin Receptor,Receptor, Endorphin,Receptor, Enkephalin,Receptor, Opiate,Receptor, Opioid,Receptor, beta-Endorphin,Receptors, beta Endorphin,beta Endorphin Receptor,beta-Endorphin Receptors
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D004361	Drug Tolerance	Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from DRUG RESISTANCE wherein an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from MAXIMUM TOLERATED DOSE and NO-OBSERVED-ADVERSE-EFFECT LEVEL.	Drug Tolerances,Tolerance, Drug,Tolerances, Drug
D004743	Enkephalin, Leucine	One of the endogenous pentapeptides with morphine-like activity. It differs from MET-ENKEPHALIN in the LEUCINE at position 5. Its first four amino acid sequence is identical to the tetrapeptide sequence at the N-terminal of BETA-ENDORPHIN.	Leucine Enkephalin,5-Leucine Enkephalin,Leu(5)-Enkephalin,Leu-Enkephalin,5 Leucine Enkephalin,Enkephalin, 5-Leucine,Leu Enkephalin
D005910	Glioma	Benign and malignant central nervous system neoplasms derived from glial cells (i.e., astrocytes, oligodendrocytes, and ependymocytes). Astrocytes may give rise to astrocytomas (ASTROCYTOMA) or glioblastoma multiforme (see GLIOBLASTOMA). Oligodendrocytes give rise to oligodendrogliomas (OLIGODENDROGLIOMA) and ependymocytes may undergo transformation to become EPENDYMOMA; CHOROID PLEXUS NEOPLASMS; or colloid cysts of the third ventricle. (From Escourolle et al., Manual of Basic Neuropathology, 2nd ed, p21)	Glial Cell Tumors,Malignant Glioma,Mixed Glioma,Glial Cell Tumor,Glioma, Malignant,Glioma, Mixed,Gliomas,Gliomas, Malignant,Gliomas, Mixed,Malignant Gliomas,Mixed Gliomas,Tumor, Glial Cell,Tumors, Glial Cell
D006822	Hybrid Cells	Any cell, other than a ZYGOTE, that contains elements (such as NUCLEI and CYTOPLASM) from two or more different cells, usually produced by artificial CELL FUSION.	Somatic Cell Hybrids,Cell Hybrid, Somatic,Cell Hybrids, Somatic,Cell, Hybrid,Cells, Hybrid,Hybrid Cell,Hybrid, Somatic Cell,Hybrids, Somatic Cell,Somatic Cell Hybrid