Chronic inhaled nitric oxide: effects on pulmonary vascular endothelial function and pathology in rats

nitric oxide: effects on pulmonary vascular endothelial func-tion and pathology in rats. J. Appl. PhysioZ. 80(l): 252-260, 1996.-Nitric oxide (NO) is a potent endogenous vasodilator produced in endothelial cells. Inhaled NO selectively vasodi-lates the pulmonary circulation. We determined the effects of chronic inhaled NO on hypoxic pulmonary vascular remodel-ing and endothelium NO-dependent and-independent vasodi-lation during normoxic and hypoxic conditions in rats. Rats were exposed to 3 wk of normoxia (N), normoxia + 20 ppm inhaled NO (N+NO), chronic hypoxia with 10 % normobaric oxygen (CH), or CH and 20 ppm inhaled NO (CH+NO). Inhaled NO decreased the number of muscular pulmonary arteries, the medial smooth muscle thickness, and the right ventricular hypertrophy associated with chronic hypoxia but had no effect on these parameters in normoxic rats. All group