Abstract
We determined the roles of liver and splanchnic vascular bed in anaphylactic hypotension in anesthetized mice. In anesthetized mice sensitized with ovalbumin (0.01 mg), an intravenous injection of 0.01 mg ovalbumin caused not only a decrease in systemic arterial pressure (Psa) from 92±1.6 (SE) to 39±2.6 mmHg but also an increase in portal venous pressure (Ppv) which persisted for 40 min after the antigen injection. The elimination of the splanchnic vascular beds, by the occlusions of the celiac and mesenteric arteries, combined with total hepatectomy attenuated anaphylactic hypotension. In addition, a head-down tilt maneuver, which could facilitate venous return in the splanchnic organs, significantly attenuated the decrease in Psa induced by an antigen injection. These results suggest that liver and splanchnic vascular beds are involved in anaphylactic hypotension presumably due to anaphylactic contraction-induced portal hypertension, which induced splanchnic congestion resulting in a decrease in circulating blood volume and thus systemic arterial hypotension. [J Physiol Sci. 2006;56 Suppl:S134]
