S26131 (compound 5) is a potent and selective MT1 melatoninergic ligand, and the K i values are 0.5 and 112 nM for MT1 and MT2 , respectively. S26131 behaves as an MT1 and MT2 antagonist. In Vitro S26131 behaves as an antagonist on MT1 and MT2 receptors with KB values of 5.32 and 143 nM, respectively. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid