Overview on Radiolabel-Free in Vitro Assays for GPCRs.

G-protein coupled receptors (GPCRs) represent important targets for drug discovery because they participate in a wide range of cellular signalling pathways that play a role in a variety of pathological conditions. The characterization of the patho-physiological profile and functional roles of new receptors is highly dependent on the availability of potent and selective ligands and new screening assays. The study of the pharmacological profile of new chemical entities is very important in order to predict the activity of drugs and their clinical adverse effect in humans. In the last decade, a large number of new in vitro radiolabel-free assays were developed and relevant information on diseases was upgraded. In particular, radiolabel-free assays led significant easy to handle and safer tools for operators. The aim of this review is to analyze these assays in terms of new drug activity and toxicology prediction and translation of non-clinical findings to humans in order to provide a powerful tool to aid drug development.