[3H]rauwolscine (alpha-yohimbine): a specific antagonist radioligand for brain alpha 2-adrenergic receptors.
[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.
D000818:Animals; D001667:Binding, Competitive; D002395:Catecholamines / Q000378:metabolism; D002417:Cattle; D002540:Cerebral Cortex / Q000378:metabolism*; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D013237:Stereoisomerism; D015016:Yohimbine / Q000378:metabolism*
D002395:Catecholamines; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D009638:Norepinephrine