title: Evidence for imidazoline binding sites in basolateral membranes from rabbit kidney.
abstract: [3H]-RX 781094 and [3H]-rauwolscine, two potent alpha 2-adrenergic antagonists, were used to characterize alpha 2 receptor in basolateral membranes from rabbit kidney. However, the following findings suggest that the imidazoline [3H]-RX 781094 binds to an heterogeneous population of binding sites: 1) dissociation plot was biphasic with a fast and slow component, 2) in saturation experiments, [3H]-RX 781094 labels 3.5 more binding sites than [3H]-rauwolscine (p less than 0.02), 3) competition studies showed that molecules with imidazoline structure completely inhibited the [3H] RX 781094 binding; in contrast, only 25% of binding was affected by non-imidazoline alpha 2 adrenergic compounds. These results suggest that in basolateral membranes from rabbit kidney, [3H] RX781094 labels alpha 2 adrenergic and non-adrenergic receptors which might be imidazoline-preferring binding sites.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D004146:Dioxanes / Q000378:metabolism*; D004147:Dioxins / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism; D019329:Idazoxan; D007093:Imidazoles / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D010646:Phentolamine / Q000378:metabolism; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013329:Structure-Activity Relationship; D015016:Yohimbine / Q000378:metabolism*
chemical_list: D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D004147:Dioxins; D007093:Imidazoles; D011942:Receptors, Adrenergic, alpha; D011956:Receptors, Cell Surface; D015016:Yohimbine; D019329:Idazoxan; D010646:Phentolamine