Are only α2-adrenergic receptors present in bovine retina?

Abstract
.alpha.-Adrenergic receptors in the bovine retina were characterized using radioreceptor assays. 3H-phentolamine (an .alpha.1- and .alpha.2-antagonist), 3H-clonidine (a preferential .alpha.2-agonist) and 3H-WB 4101 [(2,6-dimethoxyphenoxyethyl)aminoethyl-1,4-benzodioxane, an .alpha.1-antagonist] were used as radioligands, and WB 4101 and prazosin (.alpha.1-antagonists), tolazine (an .alpha.2-antagonist), yohimbine and its stereoisomers rauwolscine (preference for .alpha.2-receptors) and corynanthine (preference for .alpha.1-receptors) were used as inhibitors of radioligand binding. Only .alpha.2-adrenergic receptors were found.