Regulation of muscarinic receptor expression and function in cultured cells and in knock-out mice
| Autor: | Michael L. Schlador, Sarabeth L. Thomas, Neil M. Nathanson, Lise A. McKinnon, Marc L. Rosoff, Susan E. Hamilton |
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| Rok vydání: | 1997 |
| Předmět: |
Agonist
Mice Knockout Potassium Channels medicine.drug_class Myocardium Muscarinic acetylcholine receptor M2 General Medicine Muscarinic acetylcholine receptor M1 Chick Embryo Biology Molecular biology Receptors Muscarinic General Biochemistry Genetics and Molecular Biology Retina Mice GTP-Binding Proteins Interleukin-21 receptor Muscarinic acetylcholine receptor M5 medicine Enzyme-linked receptor Animals 5-HT5A receptor General Pharmacology Toxicology and Pharmaceutics Receptor Cells Cultured |
| Zdroj: | Life sciences. 60(13-14) |
| ISSN: | 0024-3205 |
| Popis: | We have investigated the molecular and cellular basis for the regulation of expression and function of the muscarinic acetylcholine receptors. Treatment of cultured chick cardiac cells with the agonist carbachol results in decreased levels of mRNA encoding the m2 and m4 receptors. Treatment of chick embryos in ovo with carbachol results in decreased levels of mRNA encoding the potassium channel subunits GIRK1 and GIRK4 as well as the m2 receptor. There are thus multiple pathways for the regulation of mAChR responsiveness by long-term agonist exposure. Immunoblot, immunoprecipitation, and solution hybridization analyses have been used to quantitate the regulation of mAChR expression in chick retina during embryonic development. The m4 receptor is the predominant subtype expressed early in development, while the expression of the m3 and m2 receptors increases later in development. A cAMP-regulated luciferase reporter gene has been used to demonstrate that the m2 and m4 receptors have distinct specificities for coupling to G-protein subtypes to mediate inhibition of adenylyl cyclase. This system has also been used to demonstrate that beta-arrestin1 and beta-adrenergic receptor kinase-1 act synergistically to promote receptor desensitization. We have isolated the promoter region for the chick m2 receptor gene, identified regions of the promoter required to drive high level expression in cardiac and neural cells, and have identified a region which confers sensitivity of gene expression to neurally active cytokines. Finally, in order to determine the role of individual receptor subtypes in muscarinic-mediated responses in vivo, we have used the method of targeted gene disruption by homologous recombination to generate mice deficient in the m1 receptor. |
| Databáze: | OpenAIRE |
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