title: Tricyclic antidepressant radioreceptor assay.
abstract: A radioreceptor assay for tricyclic antidepressants described here is based on the ability of these drugs to compete with [3H]-3-quinuclidinyl benzilate (3H-QNB) for binding to muscarinic cholinergic receptors in rat brain membranes. The assay is sensitive, in that in can detect, for example, 2 ng/ml nortriptyline in plasma. Seven plasma samples from depressed patients treated with nortriptyline were assayed with the radioreceptor and gas liquid chromatographic methods, and the results from these two methods were almost identical. This assay should be used cautiously, if at all, in patients treated with other drugs that have potent anticholinergic effects.
mesh_terms: D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000097:blood*; D001667:Binding, Competitive; D066298:In Vitro Techniques; D008722:Methods; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats
chemical_list: D000929:Antidepressive Agents, Tricyclic; D011813:Quinuclidinyl Benzilate