Venous endothelium reactivity to Angiotensin II: A study in primary endothelial cultures of rat vena cava and portal vein

The role of the vascular endothelium in modulating the arterial system has been widely investigated, but poorly explored at the venous site. In the present work, primary cultures of venous endothelium from rat Vena Cava (VC) and Portal Vein (PV) were established, characterized and analyzed according to their growth pattern and ability to produce nitric oxide (NO) and prostanoids (PGF_{2 α} and PGI₂), at basal state and after stimulation with Angiotensin II (Ang II, 1 μmol/L). Basal NO was detected in all examined cells in culture. Pre-incubation with Ang II increased NO production in cells from VC (but not in PV cultures), through activation of both AT₁ and AT₂ receptors. Both cultures exhibited detectable levels of PGF_{2 α} at resting conditions, which were similarly enhanced by Ang II. Basal PGI₂ levels were higher in PV, but increased after Ang II treatment in VC, with no further effect on PV cells. We conclude that endothelial cells from VC and PV exhibit important properties and react to Ang II, probably influencing the whole circulatory system. This experimental cell model gives support to further studies concerning intracellular pathways of the venous endothelium, analyzed in separate from the vascular smooth muscle wall.