M. Criado et al., Interaction between prostanoids and nitric oxide in the control of tubularfunction in rats with chronic bile duct ligation, CAN J PHYSL, 77(2), 1999, pp. 111-117
Recent work indicates that both nitric oxide and cyclooxygenase products pl
ay an important role in the renal alterations of liver cirrhosis, although
the interactions between them have not been completely established. The pur
pose of this study was to assess the effect of simultaneous blockade of nit
ric oxide synthase and cyclooxygenase in rats with chronic bile duct ligati
on and in control, sham-operated rats. Compared with control rats, chronic
bile duct ligation rats, 23-25 days after surgery, showed a decreased mean
arterial pressure, natriuresis, and kaliuresis, without differences in glom
erular filtration rate, and an increased urinary nitrite excretion. Nitric
oxide synthesis inhibition by administration of N-G-nitro-L-arginine methyl
ester induced, in control rats, an increase in mean arterial pressure, wit
hout significant changes in natriuresis or glomerular filtration rate. In c
hronic bile duct ligation rats, N-G-nitro-L-arginine methyl eater induced a
n increase in mean arterial pressure, natriuresis, and kaliuresis, together
with a reduction in urinary nitrite excretion and an increase in prostagla
ndin E-2 excretion. Cyclooxygenase inhibition with indomethacin induced in
both experimental groups a marked inhibition in urinary prostaglandin E-2 e
xcretion without significant changes in Na+ or K+ excretion, and a signific
ant increase in urinary nitrite excretion in control rats. N-G-Nitro-L-argi
nine methyl ester in addition to indomethacin prevented the indomethacin-in
duced increase in nitrite excretion and dramatically reduced sodium excreti
on in both experimental groups. Thus, the present study suggests that both
nitric oxide and cyclooxygenase products interact in the control of urinary
sodium excretion and that each system is activated in the absence of the o
ther one.