Biomaterial Database

Stable expression and functional characterization of the cloned rat mu-opioid receptor in human epidermoid carcinoma (A431) cells. 1996

H Ammer, and R Schulz

Institute of Pharmacology, Toxicology and Pharmacy, School of Veterinary Medicine, University of Munich, Germany.

Regulation of intracellular cAMP levels serves as a cellular model for chronic drug action. Since the adenylate cyclase effector system is under dual control of both stimulatory as well as inhibitory receptor systems, a permanent cell line was created in order to allow evaluation of acute and chronic opioid effects on stimulatory receptor function. For this purpose, the cloned rat mu-opioid receptor was stably expressed in human epidermoid carcinoma (A431) cells, which carries high levels of endogenous beta 2-adrenoceptors. Four out of 16 cell clones were found to express considerable amounts of [3H]diprenorphine binding sites and were further characterized. Scatchard analysis of saturation binding data revealed maximal binding capacities (Bmax) between 242.2 +/- 11 and 1,271.8 +/- 221 fmol/mg of membrane protein, whereas drug affinity was found similar among all cell clones tested (Kd = 1.4 +/- 0.2 nM). The expressed mu-receptors also mediated agonist inhibition of adenylate cyclase, indicating that these receptors are functionally coupled to intracellular signalling pathways. Long-term exposure of the cells to morphine (10 microM; 2 days) produced cellular correlates of chronic opioid action as displayed by both a decrease in the maximal degree of adenylate cyclase inhibition (tolerance) as well as an increase in overall effector activity (dependence). Thus, based on these parameters, mu-opioid receptor expressing A431 cells provide a promising tool to investigate cellular mechanisms of chronic drug action.

UI	MeSH Term	Description	Entries
D011943	Receptors, Adrenergic, beta	One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.	Adrenergic beta-Receptor,Adrenergic beta-Receptors,Receptors, beta-Adrenergic,beta Adrenergic Receptor,beta-Adrenergic Receptor,beta-Adrenergic Receptors,Receptor, Adrenergic, beta,Adrenergic Receptor, beta,Adrenergic beta Receptor,Adrenergic beta Receptors,Receptor, beta Adrenergic,Receptor, beta-Adrenergic,Receptors, beta Adrenergic,beta Adrenergic Receptors,beta-Receptor, Adrenergic,beta-Receptors, Adrenergic
D002294	Carcinoma, Squamous Cell	A carcinoma derived from stratified SQUAMOUS EPITHELIAL CELLS. It may also occur in sites where glandular or columnar epithelium is normally present. (From Stedman, 25th ed)	Carcinoma, Epidermoid,Carcinoma, Planocellular,Carcinoma, Squamous,Squamous Cell Carcinoma,Carcinomas, Epidermoid,Carcinomas, Planocellular,Carcinomas, Squamous,Carcinomas, Squamous Cell,Epidermoid Carcinoma,Epidermoid Carcinomas,Planocellular Carcinoma,Planocellular Carcinomas,Squamous Carcinoma,Squamous Carcinomas,Squamous Cell Carcinomas
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004247	DNA	A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).	DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004273	DNA, Neoplasm	DNA present in neoplastic tissue.	Neoplasm DNA
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
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
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining