Pharmacological characterization of new β-agonists using Huβ1- and Huβ2-adrenergic receptor binding assay in transfected HEK-293 cells

For compounds G4, G5 and G6 the affinity (IC50) for β1-adrenergic binding sites was of the same magnitude of that from clenbuterol. By contrast, G8 showed a 100-fold higher affinity. On β2-adrenergic receptors the binding affinity was similar for G4 and G6, but about 10-fold higher for G5 and G8 with respect to that from clenbuterol.