Ethanol predominantly constricts pre-sinusoids of isolated perfused livers of rat, guinea pig and mouse.

AIMS Ethanol constricts hepatic vessels of isolated perfused livers of rats, but not dogs. However, it is not known whether ethanol constricts or dilates the hepatic vessels in other species such as guinea pigs and mice. In addition, the sites of hepatic venoconstriction induced by ethanol were not known in rat livers. We therefore studied the effects of ethanol on the segmental hepatic vascular resistance and liver weight of mice, rats and guinea pigs. METHODS The isolated livers were portally perfused with diluted blood at constant flow. The sinusoidal pressure was measured by the double occlusion method and was used to determine the pre- and post-sinusoidal resistance. The change of liver weight was also measured. Ethanol was administered cumulatively into the perfusate to gain clinically relevant concentrations of 1-300 mM. RESULTS Ethanol dose dependently caused predominant pre-sinusoidal constriction in livers of all three species. When compared with the livers of the guinea pigs and rats, the mouse livers were the weakest in response. Dose-dependent decreases in liver weight and bile flow accompanied predominant pre-sinusoidal constriction in guinea pigs and rats. CONCLUSION Ethanol predominantly constricts pre-sinusoids in rat, guinea pig and mouse livers, although the mouse liver response was much weaker. Ethanol-induced pre-sinusoidal constriction is accompanied by reduction of liver blood volume in guinea pigs and rats.