Abstract
The significance of the carbohydrate moieties of the β-adrenergic receptor molecule in the rat brain was examined using the radioligand binding assay method. Thus, this experiment was designed to assess the effects of lectins, concanavlin A (Con A), Phaseolus vulgaris agglutinin (PHA), and wheat germ agglutinin (WGA) on the affinity of the β-adrenoceptor. The rat brain was used and the β-adrenoceptor binding assay was carried out using 3H-dihydroalprenolol as a ligand. Con A and PHA significantly caused an increase in the values of the density of β-adrenoceptor (Bmax) and a reduction in the values of the dissociation constant (Kd), but significant changes were not observed with WGA. These results strongly suggest that the carbohydrate moieties of the cell surface containing the β-adrenoceptor molecule may have a crucial role in the drug-receptor interaction, and they imply that the β-adrenoceptor molecule is a glycoprotein which contains N-linked carbohydrate chains.
