2-[¹²⁵I]iodomelatonin and [³H]melatonin Binding Assays for Melatonin Receptors

The radioligand binding assay is a powerful method to study the interaction of a ligand with its target. This technique allows not only to determine different pharmacological key parameters such as the affinity and the association and dissociation constants but also to estimate the amount of target expressed in recombinant or endogenous cells or tissues. The current detailed protocols describe the different binding assays (saturation, kinetic, and competition) that can be performed on melatonin receptors using their most commonly used and validated radioligands 2-[¹²⁵I]-iodomelatonin (2-[¹²⁵I]-MLT) and [³H]-melatonin ([³H]-MLT).