Effect of verapamil on nitric oxide synthase in a portal vein-ligated rat model: role of prostaglandin.
OBJECTIVE
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 N(w)-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 N(w)- nitro-L-arginine-treated and indomethacin-treated groups.


CONCLUSIONS
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.
Lay
Chii-Shyan
CS
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
May
C-M-Y
CM
Lee
Fa-Yauh
FY
Tsai
Yang-Te
YT
Lee
Shou-Dong
SD
Chien
Shu
S
Sinchon
Shlomoh
S