Bioactive ligands targeting ectopic olfactory receptors: Implications for therapeutic strategies

Ectopic olfactory receptors (EORs) are a class of olfactory receptors found outside the olfactory system. This review delves into the anatomical structure, tissue distribution, signalling pathways, and physiological functions modulated by EORs, and systematically categorises the bioactive ligands that specifically bind to these receptors, aiming to provide a solid scientific foundation for clinical therapeutic interventions. In this review we have analysed, meticulously and extensively, the published reports of the architectural composition of EORs, their distribution across various human systems, transmission mechanisms, biochemical processes in which they participate, and their bioactive ligands, with the goal of elucidating their significant role in human physiological processes. The EORs belong to the family of G protein-coupled receptors and are widely distributed across multiple tissues and organs, including the CNS and the digestive system. Upon binding to specific ligands, these receptors are involved in regulating a variety of physiological functions. A wide range of bioactive ligands have been shown to interact with EORs, including chemically synthesised compounds, food-derived constituents, endogenous substances, metabolic byproducts, as well as traditional Chinese medicines and their active components. The EORs are emerging as realistic drug targets and, consequently, the molecular design and development of drugs targeting EORs will open up novel therapeutic strategies for intractable diseases and malignant tumours.