Specific Binding of [3H]Rauwolscine to ?2-Adrenoceptors in Rat Cerebral Cortex: Comparison Between Crude and Synaptosomal Plasma Membranes

Abstract

[3H]Rauwolscine, a specific, potent, radiolabeled .alpha.2-antagonist, binds to distinct high- and low-affinity .alpha.2-adrenoceptors in crude membrane preparations of the rat cerebral cortex. The concentration of high-affinity .alpha.2-adrenoceptors was increased by addition of Na+ guanylnucleotides. In synaptosomal plasma membrane preparations, only the low-affinity component was found. Neither Na+ nor guanylnucleotides caused any increase in the concentration of these low-affinity receptors for [3H]rauwolscine.