Invited reviewProbing the pharmacology of G protein-coupled receptors with fluorescent ligands

- Fluorescent ligands for GPCRs can be used to study receptor pharmacology.
- Are a non-invasive, viable alternative to radioligand binding.
- Allows ligand-receptor interactions studies at the single cell and molecule level.
- Using imaging, visualization of receptor localization in native cells is possible.

G protein-coupled receptors control a wide range of physiological processes and are the target for many clinically used drugs. Understanding the way in which receptors bind agonists and antagonists, their organisation in the membrane and their regulation after agonist binding are important properties which are key to developing new drugs. One way to achieve this knowledge is through the use of fluorescent ligands, which have been used to study the expression and function of receptors in endogenously expressing systems. Fluorescent ligands with appropriate imaging properties can be used in conjunction with confocal microscopy to investigate the regulation of receptors after activation. Alternatively, through the use of single molecule microscopy, they can probe the spatial organisation of receptors within the membrane. This review focuses on the techniques in which fluorescent ligands have been used and the novel aspects of G protein-coupled receptor pharmacology which have been uncovered.This article is part of the Special Issue entitled 'Fluorescent Tools in Neuropharmacology'.