[3H]rauwolscine (Alpha-Yohimbine): A Specific Antagonist Radioligand for Brain Alpha 2-adrenergic Receptors

Eur J Pharmacol. 1981 Dec 17;76(4):461-4. doi: 10.1016/0014-2999(81)90123-0.

Abstract

[3H]Rauwolscine, a specific and potent alpha 2-antagonist radioligand, was used to characterize alpha 2-receptor binding in bovine cerebral cortex. [3H]Rauwolscine binding was reversible, stereospecific, and saturable. Association, dissociation, and saturation studies revealed one site interactions (k -1/k+1 = 1.2 nM, KD = 2.5 nM, Bmax = 160 fmol/mg protein) and competition studies indicated that [3H]rauwolscine labeled the alpha 2-receptor. Agonists inhibited [3H]rauwolscine binding in a shallow, GTP-sensitive manner. These results suggest that [3H]rauwolscine specifically labels both the high and low affinity states of the alpha 2-receptor in brain membranes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding, Competitive
  • Catecholamines / metabolism
  • Cattle
  • Cerebral Cortex / metabolism*
  • In Vitro Techniques
  • Norepinephrine / pharmacology
  • Receptors, Adrenergic / metabolism*
  • Receptors, Adrenergic, alpha / metabolism*
  • Stereoisomerism
  • Yohimbine / metabolism*

Substances

  • Catecholamines
  • Receptors, Adrenergic
  • Receptors, Adrenergic, alpha
  • Yohimbine
  • Norepinephrine