Bivalent ligands represent useful tools to investigate the phenomenon of GPCR dimerization. We synthesized bivalent ligands based on (R)-apomorphine with variations in spacer length, and assessed these compounds in functional and binding assays at the dopamine D2 receptor. The results present novel SAR for bivalent ligands targeting the D2R, and identify a relationship for spacer length with ligand potency, efficacy and affinity.
