Effect of hypercapnia with or without acidosis, L-NNA and 1400 W on endothelial permeability. A-C: Normoxic ventilation. D-F: Hypoxic ventilation. Endothelial permeability was assessed by measurement of the capillary filtration coefficient (Kfc) prior (pre maneuver) and after sustained hypoxia (post maneuver). Data are mean ± SEM. n = 3-7 each. *, significant difference (P < 0.05) between pre maneuver and post maneuver values.