title: Saturation assays of radioligand binding to receptors and their allosteric modulatory sites.
abstract: The protocols in this unit describe methods for measuring radioligand binding to sites on the GABA-A receptor complex. This system was chosen because of the fundamental role of GABA-A receptors in central nervous system function and the presence of multiple binding sites on one supramolecular complex. However, these basic techniques can be used to analyze ligand binding to a wide variety of intracellular and extracellular sites associated with ion channels, transporters, or G proteins with relatively simple modifications of the protocols (e.g., tissue preparation, buffers, assay termination techniques, incubation times, and temperatures). A saturation assay is presented to examine ligand binding to the benzodiazepine site on the GABA-A receptor, while a second protocol uses a similar technique to examine the binding site for GABA in this complex.
authors.affiliation: National Institute of Diabetes, Digestive, and Kidney Diseases, Bethesda, Maryland, USA.
authors.forename: A
authors.initials: A
authors.lastname: Basile
mesh_terms: D000495:Allosteric Site; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D005442:Flumazenil / Q000378:metabolism; D008024:Ligands; D009118:Muscimol / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011869:Radioligand Assay / Q000379:methods*; D051381:Rats; D011963:Receptors, GABA-A / Q000737:chemistry / Q000378:metabolism*; D014316:Tritium / Q000032:analysis; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D008024:Ligands; D009419:Nerve Tissue Proteins; D011963:Receptors, GABA-A; D014316:Tritium; D009118:Muscimol; D005442:Flumazenil; D005680:gamma-Aminobutyric Acid