title: Antagonist/agonist-preferring alpha-adrenoceptors or alpha 1/alpha 2-adrenoceptors?
abstract: Yohimbine and some stereoisomeric alkaloids inhibited the binding of 3H-clonidine and 3H-WB-4101 to rat cerebral cortex membranes. Rauwolscine and yohimbine had much higher affinity to the 3H-clonidine than to the 3H-WB-4101 site, whereas the reverse was true for corynanthine. The results indicate that the 3H-clonidine site is an alpha 2-adrenoceptor and not an agonist-selective site whereas the 3H-WB-4101 site is an alpha 1-andrenoceptor and not an antagonist-selective site.
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000378:metabolism*; D000317:Adrenergic alpha-Antagonists / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D003000:Clonidine / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D010883:Piperoxan / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000032:analysis / Q000378:metabolism*; D015016:Yohimbine / Q000031:analogs & derivatives / Q000378:metabolism*
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D010883:Piperoxan; D003000:Clonidine