Molecular pharmacology of V_1a vasopressin receptors

1. 1. Vasopressin, a mammalian neurohypophysial peptide hormone, has diverse physiological actions. 2. 2. Pharmacological studies, using a range of mammalian tissues, have identified three subtypes of vasopressin receptor. 3. 3. The V_1a subtype of vasopressin receptor is widely distributed and mediates many central and peripheral actions of vasopressin. 4. 4. The development of subtype-selective vasopressin analogues has provided valuable tools for pharmacological and physical studies of the V_1a receptor protein. 5. 5. Pharmacological differences indicate species heterogeneity in the characteristics of V_1a receptors and in the expression of hepatic V_1a receptors. 6. 6. The cloning of neurohypophysial hormone receptor proteins allows structural and functional comparison of the V_1a vasopressin receptors with other G-protein-coupled receptors.