Substâncias vasoativas e a modulação do sistema microvascular hepático

Abstract

The architecture of the hepatic microvascular system, a unique and complex vascular system, is well suited to the functions of the organ. Different factors, including endothelial vasoactive substances, participate in the modulation of the vascular resistance through the liver adequating the liver perfusion to the homeostatic needs. The liver is eminently a maintainer of internal stability.

Portal hypertensive response to kinin

“…Most of the compounds and pathways that mediate this BK effect are expressed in the liver and are likely to participate in intrahepatic vascular tone control. This is most likely to be true of intra-hepatic vessels that are structurally similar to the vessels where the BK vasodilatory effect has been demonstrated, i.e., the portal vein, hepatic artery, and their branches (Loureiro-Silva et al 1999).…”

“…Excluding the hepatic artery and its branches, which are responsible for only 20% to 40% of the blood entering the liver, the intra-hepatic circulation is maintained at very low pressure in physiological conditions. The vascular tone in portal venules, sinusoids, and hepatic venules is actively controlled by several relaxing and contracting substances, including BK , Loureiro-Silva et al 1999, 2001, Gioli-Pereira et al 2005, Nagaoka et al 2006.…”