Transmural pressure inhibits nitric oxide release from human endothelial cells

We examined the effect of transmural pressure on histamine-stimulated nitric oxide release from cultured endothelial cells prepared from human umbilical cord veins. PO2 and pH were kept constant throughout the experiments. Various levels of transmural pressure and atmospheric pressure (40, 80, 120 and 160 mm Hg) were applied. Nitric oxide release was inhibited in a pressure-dependent manner. The inhibitory effects were reversible, and nitric oxide had no effect on the morphology of the cells. Our results suggest that transmural pressure-mediated inhibition of nitric oxide release contributes to pressure-induced vasoconstriction and reduced endothelium-dependent relaxation in patients with hypertension.