Effect of isosorbide dinitrate on gastric blood flow in rats with liver cirrhosis determined by analyzing gastric blood flow, portal vein pressure and blood gas

We investigated the effects of isosorbide dinitrate (IDN) on gastric blood flow (GBF), portal venous pressure (PVP) and blood gas of rats with liver cirrhosis (LC) accompanied by portal hypertension. Thirty male Wistar rats (LC in 17 and normal in 13) were used. Before and after IDN administration, GBF, PVP and blood gas in the femoral artery and portal vein were measured. Portal blood oxygen concentration was estimated by calculating the ratio of PO2 in portal blood and that in arterial blood (PpvO2/PaO2) of each rat. The GBF in the LC rats was significantly lower than that in the normal rats. In the LC group, IDN administration significantly increased the GBF. The PpvO2/PaO2 value in the group with LC was significantly lower after IDN administration than that before IDN administration. In the investigation whether changes in PVP or Ppv/PaO2 contributed more to the change in GBF after IDN administration, a significant correlation was found between rates of change in GBF and PpvO2/PaO2 were significantly correlated (r= -0.733, p <0.05). The effect of IDN on changes in the stomach accompanying portal hypertension is mainly attributable to a decrease in preload, which suppresses inflow to the stomach, as reflected by a decrease in PpvO2/ PaO2, rather than to a decrease in afterload on GBF, as reflected by a decrease in PVP.