Am. Ramirez et al., EFFECTS OF THE INHIBITION OF NITRIC OXID SYNTHESIS IN THE HEMODYNAMICAND EXCRETORY FUNCTIONS OF RATS WITH BILIARY CIRRHOSIS, Nefrologia, 14(6), 1994, pp. 656-662
Liver cirrhosis is associated with elevated blood nitrid oxide (NO) le
vels. In the present study we have evaluated the role of NO in the ren
al hemodynamic and excretory abnormalities present in an experimental
model of biliary cirrhosis. The experiments were performed in Munich-W
istar rats, 25 days after bile duct ligation (BDL) or sham operation (
controls). Intravenous infusion of NO synthesis inhibitor (L-NAME, 1,5
and 10 mu g/Kg/min) did not alter mean arterial pressure (MAP) in con
trol animals and decreased renal papillary blood flow (PBF, laser-dopp
ler flowmetry) in a dose-dependent manner (5.4 +/- 1.6 %, 16.2 +/- 2.6
% and 26.3 +/- 3.3 %, respectively). In the BDL group, basal MAP was
lower and increased significantly with the first dose of L-NAME (from
90.6 +/- 3.8 to 105.2 +/- 5.1 mmHg) and kept increasing with the follo
wing doses (127.4 +/- 4.2 and 133.7 +/- 4.2 mmHg). In these BDL animal
s, basal PBF was significantly lower (40.3 +/- 3.8 %) than that of the
controls and, L-NAME administration induced higher increases in papil
lary resistance than in the controls. In control animals prepared for
renal clearances and subjected to the same infusion dosage, L-NAME adm
inistration did not change MAP and slightly increased diuresis and nat
riuresis only with the highest dose of the inhibitor. In contrast, in
the BDL animals, MAP, diuresis and natriuresis increased significantly
after infusion of the NO synthesis inhibitor ti-om the first dose and
remained elevated throughout the experiment. Renal vasoconstriction i
nduced by the NO synthesis inhibitor was also significantly greater in
the BDL group. These results indicate that anesthetized rats with bil
iary cirrhosis show a higher systemic and renal sensitivity to NO synt
hesis inhibition. This result suggests that NO participates in the low
er arterial pressure and renal alterations of the animals with biliary
cirrhosis.