Phenoxybenzamine is more potent in inactivating alpha 1- than alpha 2-adrenergic receptor binding sites.
The effects of phenoxybenzamine on alpha 1- and alpha 2-adrenergic receptor binding sites were examined directly using radioligand binding assays of the antagonist drugs [125I]BE 2254 and [3H]rauwolscine, respectively, in homogenates of rat cerebral cortex. Treatment with phenoxybenzamine caused an irreversible, dose-dependent decrease in the density of both alpha 1- and alpha 2-adrenergic receptors. Phenoxybenzamine was approximately 250-fold more potent at decreasing alpha 1-adrenergic receptor density than it was at decreasing alpha 2-adrenergic receptor density.
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D010627:Phenethylamines / Q000494:pharmacology; D010643:Phenoxybenzamine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000145:classification / Q000187:drug effects*; D044024:Tetralones; D015016:Yohimbine / Q000494:pharmacology
D010627:Phenethylamines; D011942:Receptors, Adrenergic, alpha; D044024:Tetralones; D010643:Phenoxybenzamine; D015016:Yohimbine; C010652:BE 2254