V2 Receptor 

V2 receptor (V2R/AVPR2) is a renal G protein-coupled receptor that mediates arginine vasopressin control of body water homeostasis in distal tubules and collecting ducts[1]. Mechanistically, AVP activates V2R-dependent Gs-adenylate cyclase-cAMP signaling, which promotes AQP2 translocation in collecting duct principal cells and increases water reabsorption[1][2]. Quantitative phosphoproteomics further supports multiple V2R-dependent signaling pathways in renal collecting duct cells, making V2R a central experimental entry point for urine-concentrating mechanisms[3]. In disease models, loss-of-function mutations in V2R cause X-linked nephrogenic diabetes insipidus, whereas excessive AVP-V2R activity contributes to water retention and hyponatremia[4][5]. Compared with related isoforms, V2R primarily regulates urine osmotic concentration, while V1a receptors promote natriuresis and V1b receptors regulate potassium secretion in distal nephron segments[6]. For experimental applications, dDAVP/desmopressin remains a standard V2R-selective agonist, and tolvaptan is a selective oral V2R antagonist used to study and treat hyponatremia[7][5]. Recent cryo-EM structures show that tolvaptan and Mambaquaretin bind the V2R orthosteric site in distinct inactive conformations, supporting structure-guided antagonist design[8].- V2R links vasopressin sensing to cAMP signaling, AQP2 trafficking, and renal water reabsorption.- V2R differs from V1a and V1b by its dominant role in urine concentration.- dDAVP and tolvaptan support agonist-antagonist studies of V2R-dependent water-balance disorders.