What is the primary mechanism of action of Desmopressin?

• A. Inhibition of thrombin
• B. Agonist activity at V2 receptors
• C. Stimulation of platelets
• D. Direct vasodilation

Answer: (B)

Desmopressin is primarily used in the treatment of conditions such as diabetes insipidus and von Willebrand's disease due to its effects on renal water retention and hemostasis. The main mechanism of action of Desmopressin is its agonist activity at V2 receptors, which are located in the collecting ducts of the kidneys. When Desmopressin binds to these V2 receptors, it stimulates the reabsorption of water by increasing the permeability of the renal tubules. This leads to a decrease in urine output and helps maintain appropriate fluid balance in the body.

In patients with von Willebrand's disease, Desmopressin promotes the release of von Willebrand factor from endothelial cells, aiding in platelet adhesion and aggregation, thus improving clotting. The focus remains primarily on the V2 receptor activity, which underlies Desmopressin's therapeutic effects in both water retention and hemostasis.

This comprehensive understanding of how Desmopressin functions focuses on its receptor interaction, clarifying its role in clinical settings.