Binding to alpha-adrenergic receptors: differential pharmacological potencies and binding affinities of benzodioxanes

Eur J Pharmacol. 1979 Aug 15;57(4):317-28. doi: 10.1016/0014-2999(79)90494-1.


We have compared the influence of a series of benzodioxane alpha-adrenergic antagonists on 3H-WB-4101 and 3H-clonidine binding to alpha-receptor sites in the brain and peripheral tissues with their pharmacological properties. The drug specificity of 3H-WB-4101 binding is quite similar in central and peripheral tissues. Pharmacological potencies of benzodioxanes at postsynaptic alpha-receptors in the rat vas deferens correlate with potencies at 3H-WB-4101 but not at 3H-clonidine binding sites. These findings suggest pharmacological effects of these drugs are mediated by "alpha-1 postsynaptic receptors" labeled by 3H-WB-4101. For several benzodioxanes absolute pharmacological potencies at postsynaptic alpha-receptors of the rat vas deferens are substantially less than their potencies at 3H-WB-4101 sites. The potencies of benzodioxane analogues at 3H-clinidine binding sites are similar to their pharmacological potencies at presynaptic autoreceptors in the rat vas deferens.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cerebral Cortex / metabolism
  • Clonidine / pharmacology
  • Hydroxydopamines / pharmacology
  • Male
  • Muscle Contraction / drug effects
  • Norepinephrine / metabolism
  • Piperidines / metabolism*
  • Piperoxan / analogs & derivatives
  • Piperoxan / metabolism*
  • Piperoxan / pharmacology
  • Rats
  • Receptors, Adrenergic / metabolism*
  • Receptors, Adrenergic, alpha / metabolism*
  • Synaptosomes / metabolism


  • Hydroxydopamines
  • Piperidines
  • Receptors, Adrenergic
  • Receptors, Adrenergic, alpha
  • Piperoxan
  • Clonidine
  • Norepinephrine