Distribution and pharmacological characterization of muscarinic-cholinergic receptors in the cockroach brain.
The binding of [3H]quinuclidinyl benzilate to a cockroach brain preparation was investigated. Specific binding was saturable with a Kd of 0.25 nM and Scatchard analysis indicated a Bmax of 604 pmol/mg protein. Kinetic analysis indicated that the ligand is binding in a complex fashion while dissociation followed a simple kinetic process. The pharmacology of the site was typical of muscarinic receptors but the site cannot be characterized in terms of vertebrate muscarinic-receptor subtypes. Affinity of the receptor for agonists was modulated by Mg2+ and guanylylimidodiphosphate but not by pertussis toxin indicating the involvement of a pertussis-toxin insensitive G-protein. Carbamylcholine did not inhibit basal or forskolin-stimulated adenylate cyclase activity. The binding site was localized autoradiographically and was restricted to the median and lateral calyces of the brain.
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Pesticide Research Center, Michigan State University (Neuroscience Program), East Lansing 48824-1311.
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Hollingworth
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D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D002038:Bungarotoxins / Q000378:metabolism; D003058:Cockroaches / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D007700:Kinetics; D008297:Male; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism*; D011978:Receptors, Nicotinic / Q000378:metabolism; D014316:Tritium
D002038:Bungarotoxins; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D014316:Tritium; D011813:Quinuclidinyl Benzilate; D000242:Cyclic AMP