PORTAL HYPOTENSIVE EFFECTS OF DL-028 AND PRAZOSIN ON PORTAL HYPERTENSIVE RATS

The portal hypotensive effects of prazosin and DL-028 (chemical name: 3-dihydroimidazo[1,2-c]quinazolin-5(6H)-one(27b)), a synthetic alpha(1 )-adrenoceptor antagonist, were assessed in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Spr ague-Dawley rats. Two weeks after ligation, when the hyperdynamic stat e was stabilized the rats were anesthetized after an overnight fast an d cannulated for measuring mean arterial pressure (MAP), portal venous pressure (PVP), cardiac index (CI) and heart rate (HR). Both DL 028 a nd prazosin (1, 3.3 and 10 mu g/kg) induced dose-dependent decreases o f PVP and MBP after intravenous infusion, with effects lasting for lon ger than 30 min. The maximum percentage reduction of PVP after DL-028 was 10, 10 and 15%, respectively, for the dosages given (1, 3.3 and 10 mu g/kg), and 5, 12 and 25%, respectively, after prazosin. CI was not changed by either drug. HR was not changed by either drug except DL- 028 at 10.0 mu g/kg with a bradycardiac effect. Our results showed tha t both DL-028 and prazosin reduced PVP in portal hypertensive rats.