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Evidence for normal nitric oxide—mediated vasodilator tone in conscious rats with cirrhosis
Author(s) -
Sogni Philippe,
Moreau Richard,
Ohsuga Masaru,
Cailmail Stephane,
Oberti Frederic,
Hadengue Antoine,
Pussard Eric,
Lebrec Didier
Publication year - 1992
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840160421
Subject(s) - nitric oxide , portal hypertension , medicine , vascular resistance , vasodilation , portal venous pressure , endocrinology , cirrhosis , hemodynamics , arginine , nitroarginine , hyperdynamic circulation , blood pressure , chemistry , nitric oxide synthase , biochemistry , amino acid
Because it has been hypothesized that the hyperkinetic circulation in portal hypertension is the result of increased synthesis of nitric oxide, we compared the hemodynamic effects of nitric oxide synthesis—specific agonist (L‐arginine) and antagonist between normal and cirrhotic conscious rats. The dose‐response curves showed that L‐arginine significantly decreased arterial pressure and increased heart rate. These changes started at the 200 mg/kg dose and were similar in both groups of rats. In both groups of rats N G ‐monomethyl—L‐arginine (25 mg/kg) significantly decreased cardiac output by 35%. In cirrhotic rats, N G ‐monomethyl—Larginine decreased portal pressure from 15.3 ± 0.9 mm Hg to 13.6 ± 0.7 mm Hg and portal tributary blood flow from 7.8 ± 0.7 ml · min −1 · 100 gm −1 to 5.9 ± 0.7 ml · min −1 · 100 gm − ; it significantly increased portal territory vascular resistance from 950 ± 108 dyn · sec · cm −5 · 100 gm −1 × 10 3 to 1,579 ± 258 dyn · sec · cm −5 · 100 gm −1 × 10 3 . In normal rats, portal tributary blood flow decreased similarly, by 27%, and portal territory vascular resistance increased by 55%. In neither group was hepatic arterial blood flow altered. Before and after N G ‐monomethyl‐L‐arginine administration, arterial cyclic GMP concentrations were not significantly different between normal and cirrhotic rats. In conclusion, this study shows evidence of a normal role for nitric oxide—mediated vasodilatation in rats with cirrhosis and that inhibition of nitric oxide synthesis reduces portal hypertension. These results did not support the hypothesis that nitric oxide synthesis is increased in cirrhosis. (HEPATOLOGY 1992;16:980–983.)