title: Autoradiographic differentiation of multiple benzodiazepine receptors by detergent solubilization and pharmacologic specificity.
abstract: We have used light microscopic autoradiography to localize differentially Type 1 and 2 benzodiazepine receptors using pharmacologic and detergent treatment techniques. The triazolopyridazine CL218872 has preferential affinity for Type 1 receptors from which it displaces [3H]flunitrazepam selectivity. In biochemical experiments [3H]flunitrazepam binding sites with pharmacologic properties of Type 2 receptors are preferentially solubilized from brain membranes by detergents. We have now treated rat brain slices either with CL218872 or 2% sodium cholate and evaluated the autoradiographic distribution of [3H]flunitrazepam-labeled receptors. Whether calculated from the drug or detergent treated preparations, the relative densities of apparent Type 1 and 2 receptors are the same. Thus differential sensitivity to determine solubilization distinguishes the same two populations of receptors as Type 1 and 2 specific drugs.
mesh_terms: D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D005445:Flunitrazepam / Q000378:metabolism; D009434:Neural Pathways / Q000378:metabolism; D011724:Pyridazines / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011963:Receptors, GABA-A; D013378:Substantia Nigra / Q000378:metabolism
chemical_list: D011724:Pyridazines; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D005445:Flunitrazepam; C021604:CL 218872