Rational Design, Synthesis, and Evaluation of Fluorescent CB(2) Receptor Ligands for Live-Cell Imaging: A Comprehensive Review

The cannabinoid receptors CB(1) and CB(2) are class A G protein-coupled receptors (GPCRs) that are activated via endogenous lipids called endocannabinoids. The endocannabinoid system (ECS) plays a critical role in the regulation of several physiological states and a wide range of diseases. In recent years, drug discovery approaches targeting the cannabinoid type 2 receptor (CB(2)R) have gained prominence. Particular attention has been given to selective agonists targeting the CB(2) receptors to circumvent the neuropsychotropic side effects associated with CB(1) receptors. The pharmacological modulation of CB(2)R holds therapeutic promise for various diseases, such as inflammatory disorders and immunological conditions, as well as pain management and cancer treatment. Recently, the utilization of fluorescent probes has emerged as a valuable technique for investigating the interactions between ligands and proteins at an exceptional level of spatial and temporal precision. In this review, we aim to examine the progress made in the development of fluorescent probes targeting CB(2) receptors and highlight their significance in facilitating the successful clinical translation of CB(2)R-based therapies.