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Comparison of subcellular distribution and functions between exogenous and endogenous M1 muscarinic acetylcholine receptors
- Source :
- Life Sciences. 93:17-23
- Publication Year :
- 2013
- Publisher :
- Elsevier BV, 2013.
-
Abstract
- Aims Recombinant systems have been used for evaluating the properties of G-protein-coupled receptors (GPCRs) on the assumption of cell surface expression. However, many GPCRs, including muscarinic acetylcholine receptors (mAChRs), have also been reported to be distributed in intracellular organelles in native tissues and cell lines. In this study, we compared the pharmacological profiles of exogenously and endogenously expressed M1-mAChRs, and evaluated the functional properties of these receptors. Main methods Recombinant M1-mAChRs were expressed exogenously in Chinese hamster ovary cells (CHO-M1 cells) and compared with endogenously expressed M1-mAChRs in N1E-115 neuroblastoma cells. The pharmacological and functional profiles were evaluated using cell-permeable antagonists (1-quinuclidinyl-benzilate (QNB), pirenzepine and atropine) and cell-impermeable antagonists (N-methylscopolamine (NMS) or MT-7). Key findings M1-mAChRs were seen at the cell surface and intracellular sites in both cell lines. Under whole cell conditions, intracellular M1-mAChRs were mainly recognized by cell-permeable ligands, but scarcely by cell-impermeable ligands (at less than 100 nM). In CHO-M1 cells, M1-mAChR activation by carbachol resulted in Ca 2 + mobilization, ERK1/2 phosphorylation and a reduction in thymidine incorporation, all of which were completely inhibited by MT-7, indicating the involvement of surface M1-mAChRs. In N1E-115 cells, Ca 2 + mobilization occurred through surface M1-mAChRs, whereas ERK1/2 phosphorylation and acceleration of thymidine incorporation were mediated through intracellular M1-mAChRs. Significance Exogenous and endogenous M1-mAChRs are present at both the cell surface and the intracellular organelles, and the pharmacological properties of geographically distinct M1-mAChRs are different, and may depend on cell background and/or exogenous or endogenous origin.
- Subjects :
- Atropine
Blotting, Western
CHO Cells
Biology
Tritium
General Biochemistry, Genetics and Molecular Biology
Mice
Radioligand Assay
Cricetulus
Cricetinae
Muscarinic acetylcholine receptor
Muscarinic acetylcholine receptor M5
Muscarinic acetylcholine receptor M4
Animals
General Pharmacology, Toxicology and Pharmaceutics
Receptor
Organelles
Analysis of Variance
Microscopy, Confocal
Chinese hamster ovary cell
Receptor, Muscarinic M1
Muscarinic acetylcholine receptor M3
Muscarinic acetylcholine receptor M2
Pirenzepine
General Medicine
N-Methylscopolamine
Recombinant Proteins
Quinuclidinyl Benzilate
Biochemistry
Calcium
Intracellular
Subjects
Details
- ISSN :
- 00243205
- Volume :
- 93
- Database :
- OpenAIRE
- Journal :
- Life Sciences
- Accession number :
- edsair.doi.dedup.....d828e0f1fbe1af21fd0810b92ad087af