Basic Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Apr 21, 2006; 12(15): 2351-2356
Published online Apr 21, 2006. doi: 10.3748/wjg.v12.i15.2351
Effect of verapamil on nitric oxide synthase in a portal vein-ligated rat model: Role of prostaglandin
Chii-Shyan Lay, CMY May, Fa-Yauh Lee, Yang-Te Tsai, Shou-Dong Lee, Shu Chien, Shlomoh Sinchon
Chii-Shyan Lay, Division of Hepatology and Gastroenterology, Department of Internal Medicine, China Medical University Hospital, Taichung, China
CMY May, Fa-Yauh Lee, Yang-Te Tsai, Shou-Dong Lee, Division of Gastroenterology, Department of Internal Medicine, Veterans General Hospital, Taipei, National Yang-Ming University School of Medicine, Taipei, China
Shu Chien, Institute of Biomedical Sciences, Academia Sinica, Taiwan, China
Shlomoh Sinchon, Department of Medicine, Columbia University, New York University Medical Center, New York, USA
Supported by the grant from China Medical University Hospital, Taichung, Taiwan, China
Correspondence to: Chii-Shyan Lay, MD, PhD, Division of Hepatology and Gastroenterology, Department of Internal Medicine, China Medical University Hospital, No.2, Yuh-Der Road, Taichung, 404, Taiwan, China. laycs000@yahoo.com
Telephone: +886-4-22062121-2019 Fax: +886-4-22038883
Received: October 7, 2005
Revised: November 2, 2005
Accepted: November 10, 2005
Published online: April 21, 2006
Abstract

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.

Keywords: Verapamil, Nitric oxide synthase, Portal hypertension