A multitude of effects has been attributed to melatonin at pmol/L to mmol/L concentrations. More than fifteen targets have been proposed for melatonin but only few of them are well characterized. The current guidelines intend to provide a framework to improve and rationalize the characterization of melatonin targets and effects. They should be considered as mandatory guidelines and minimum requirements for manuscripts submitted to the Journal of Pineal Research.

Irreversible probes have been proven to be useful pharmacological tools in the study of structural and functional features in drug receptor pharmacology. They have been demonstrated to be particularly valuable for the isolation and purification of receptors. Furthermore, irreversible probes are helpful tools for the identification and characterization of binding sites, thereby supporting the advancement of rational drug design. In this Minireview, we provide insight into universal strategies and guidelines to successfully synthesize irreversible probes that target G protein-coupled receptors (GPCRs). We provide an overview of commonly used chemoreactive and photoreactive groups, and make a comparison of their properties and potential applications. Furthermore, there is a particular focus on synthetic approaches to introduce these reactive groups based on commercially available reagents.