Effect of vasopressin V (OPC-21268) and V2 (OPC-31260) antagonists on renal hemodynamics and excretory function.

Our objective was to assess the effect of endogenous AVP on renal hemodynamics and excretory function. We measured mean arterial pressure (MAP), renal blood flow (RBF), glomerular filtration rate (GFR) and urine osmolality before and after the intravenous infusion of a V1 antagonist (OPC-21268), a V2 antagonist (OPC-31260) and their vehicle (saline) in anesthetized male Wistar rats. The infusion of the V2 antagonist increased the urine flow rate and reduced the urine osmolality significantly (p < 0.05). The infusion of saline and the V1 antagonist did not change the urine flow rate or the urine osmolality. The infusion of saline, the V1 antagonist and the V2 antagonist had no effect on MAP, RBF or GFR. These results suggest that endogenous AVP plays a critical role in the regulation of renal water reabsorption mediated through the V2 receptor.