Published online Apr 21, 2006. doi: 10.3748/wjg.v12.i15.2351
Revised: November 2, 2005
Accepted: November 10, 2005
Published online: April 21, 2006
AIM: To investigate the effects of verapamil on nitric oxide (NO) synthesis in a portal vein-ligated rat model.
METHODS: Systemic and splanchnic hemodynamics were measured by radiolabeled microspheres in portal hypertensive rats after acute administration of verapamil (2 mg/kg) on chronic treatment with Nw–nitro-L-arginine (NNA)(80 mg/kg) and/or indomethacin (2 mg/kg) .
RESULTS: Verapamil (2 mg/kg) caused a marked fall in both arterial pressure and cardiac output accompanied by an insignificant change in the portal pressure and no change in portal venous inflow. This result suggested that verapamil did not cause a reduction in portal vascular resistance of portal hypertensive rats, which was similar between Nw- nitro–L-arginine-treated and indomethacin-treated groups.
CONCLUSION: In portal hypertensive rats pretreated with NNA and/or indomethacin, acute verapamil administration can not reduce the portal pressure, suggesting that NO and prostaglandin play an important role in the pathogenesis of splanchnic arterial vasodilation in portal hypertension.