Acetylcholine stimulates GTP binding to G proteins in rat striatum.
To evaluate the role of G proteins in acetylcholine (ACh)-mediated signal transduction, a novel assay to measure [35S]GTP gamma S binding to rat striatal membranes was standardized. ACh and carbamylcholine (CCh) stimulated the high affinity [35S]GTP gamma S binding to striatal membranes by up to 45% in a concentration-dependent manner. A time course study revealed that 0.1 microM CCh stimulated [35S]GTP gamma S binding by 26% at 4 min and 20% at 15 min. CCh-stimulated [35S]GTP gamma S binding was inhibited by atropine, N-methylscopolamine and pirenzepine. Oxotremorine (1 microM), a partial muscarinic agonist, maximally stimulated the binding to striatal membranes by only 25%.
Ravindra
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Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta 30912-2300.
Aronstam
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RS
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D003342:Corpus Striatum / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D051381:Rats; D011919:Rats, Inbred Strains
D016244:Guanosine 5'-O-(3-Thiotriphosphate); D011092:Polyethylene Glycols; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D000109:Acetylcholine