Pre-sinusoidal vessels predominantly contract in response to anaphylaxis in isolated rabbit liver

Abstract

The pathophysiology of the hepatic vascular response to anaphylaxis in rabbit is not known. We studied effects of anaphylaxis on hepatic vascular resistances and liver weight in isolated perfused livers derived from sensitized New Zealand white rabbits. Sensitization was performed by a subcutaneous injection of ovalbumin (1 mg) four times at one week intervals. The livers were perfused portally and recirculatingly at constant flow with diluted blood. With the use of the double-occlusion technique to estimate the hepatic sinusoidal pressure, pre-sinusoidal resistance (Rpre) and post-sinusoidal resistance (Rpost) were calculated. An injection of the antigen (2 mg) into the perfusate caused hepatic venoconstriction, reflected by an increase in portal vein pressure. This anaphylactic hepatic venoconstriction was characterized by an increase in Rpre greater than Rpost, and was accompanied by a liver weight loss. In conclusion, anaphylaxis causes predominantly pre-sinusoidal constriction and a decrease in liver blood volume in isolated sensitized-rabbit livers. [Jpn J Physiol 55 Suppl:S90 (2005)]