Evidence for imidazoline binding sites in basolateral membranes from rabbit kidney

Biochem Biophys Res Commun. 1987 Sep 30;147(3):1055-60. doi: 10.1016/s0006-291x(87)80177-8.

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

  • Adrenergic alpha-Antagonists / metabolism*
  • Animals
  • Binding, Competitive
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Dioxanes / metabolism*
  • Dioxins / metabolism*
  • Epithelium / metabolism
  • Idazoxan
  • Imidazoles / metabolism*
  • Kidney / metabolism*
  • Phentolamine / metabolism
  • Rabbits
  • Receptors, Adrenergic, alpha / metabolism*
  • Receptors, Cell Surface / metabolism*
  • Structure-Activity Relationship
  • Yohimbine / metabolism*

Substances

  • Adrenergic alpha-Antagonists
  • Dioxanes
  • Dioxins
  • Imidazoles
  • Receptors, Adrenergic, alpha
  • Receptors, Cell Surface
  • Yohimbine
  • Idazoxan
  • Phentolamine