Effects of nitric oxide synthase inhibitor in two-week oral treatment on hyperdynamic circulatory statein cirrhotic rats

AIM:To investigate the ef ects of low dosage of nitric oxide synthase(NOS)inhibitor N^G-nitro-L-arginine methyl ester(L-NAME)in two-week treatment on the hyperdynamic circulatory state in rats with cirrhosis.METHODS:Cirrhosis model was induced in male SD rats by injection of 60%CCl4 oily solution subcutaneously.Cirrhotic rats were treated with L-NAME(0.5 mg kg^-1d^-1)by gavage for two weeks.Mean arterial pressure(MAP), portal pressure(PP), cardiac output(CO), cardiac index(CI), splanchnic vascular resistance(SVR), splanchnic blood flow(SBF)and serum nitrite levels were determined in L-NAME-treated, L-NAME-untreated cirrhotic rats and controls by using 57Co-labled microsphere technique and a fluorometric assay, respectively.RESULTS:Untreated cirrhotic rats had significantly lower MAP, SVR and higher PP, CO, CI, SBF and nitrite concentration than those of the controls(all, P<0 01).In treated cirrhotic rats, L-NAME significantly at enuated the increase of CO, CI, SBF, nitrite concentration and the decrease of MAP and SVR.In treated cirrhotic rats, L-NAME induced a marked decrease of nitrite concentration than untreated cirrhotic rats(1.471 0.907)mol/L vs(4.204 1.253)mol/L, P<0 01].CONCLUSION:The endogenous NO may play an important role in the changes of hemodynamics pat ern in cirrhosis, andhyperdynamic circulatory state in rats with cirrhosis can be ameliorated by oral two-week administration of lower dose of L-NAME.