Modulation of the vasopressin system for the treatment of CNS diseases.

Vasopressin (also known as arginine vasopressin [AVP]) is a small cyclic peptide that acts at the V1a, V1b and V2 GPCRs to regulate a wide range of physiological functions, including vasoconstriction, smooth muscle contractility, response to stress, and excretion of water and sodium via the kidney. The potential therapeutic applications of AVP receptor ligands have prompted significant interest in this target within the pharmaceutical research community, and several small-molecule drugs targeting the AVP receptor have reached the market, mainly for cardiovascular indications. The development of AVP receptor modulators for the treatment of CNS indications has proven more challenging, and is the focus of this review. The regulatory role of AVP on the hypothalamic-pituitary-adrenal (HPA) axis suggests potential uses for AVP receptor modulators in various CNS indications, including depression, anxiety and post-traumatic stress disorder. Several clinical trials of V1a and V1b receptor antagonists in CNS indications have been conducted, but none of these drugs have reached the market. In recent years, the discovery of the key role of AVP in modulating complex social behaviors has provided a unique opportunity to understand the physiological mechanisms of social interactions. Ultimately, the ongoing research in this field may enable the development of treatments to alleviate the social deficits associated with conditions such as autism and schizophrenia. Given the large unmet medical need in these areas, a renewed interest in the field of CNS-penetrant AVP receptors modulators is expected.