title: Direct measurement of vascular alpha 1-adrenoceptors.
abstract: alpha-Adrenoceptors play an important role in regulating vascular tone. [125I]BE2254, a high affinity antagonist, has been utilized to label alpha 1-receptors in membrane preparations from rabbit aorta. [125I]BE2254 specifically labels a single class of binding sites with the characteristics of alpha 1-receptors. Catecholamines compete for [125I]BE2254 binding stereospecifically and with the characteristic alpha-adrenergic potency series (-)-adrenaline greater than or equal to (-)-noradrenaline much greater than (-)-isoprenaline. The alpha 1-adrenoceptor selective antagonist prazosin is much more potent than yohimbine in competing for the [125I]BE2254 binding sites, which suggests that the alpha-adrenoceptor identified is predominantly of the alpha 1 subtype. The extension of radioligand binding techniques to individual rabbit aortas should simplify the study of vascular alpha-adrenoceptor regulation.
authors.forename: B B
authors.initials: BB
authors.lastname: Hoffman
authors.forename: G
authors.initials: G
authors.lastname: Tsujimoto
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D009131:Muscle, Smooth, Vascular / Q000032:analysis*; D010627:Phenethylamines / Q000378:metabolism* / Q000494:pharmacology; D010646:Phentolamine / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism; D011817:Rabbits; D011869:Radioligand Assay; D011942:Receptors, Adrenergic, alpha / Q000032:analysis*; D044024:Tetralones; D015016:Yohimbine / Q000378:metabolism
chemical_list: D000317:Adrenergic alpha-Antagonists; D010627:Phenethylamines; D011942:Receptors, Adrenergic, alpha; D044024:Tetralones; D015016:Yohimbine; C010652:BE 2254; D011224:Prazosin; D010646:Phentolamine