[Experimental study of hypoxic pulmonary hypertension induced by nitric oxide in rats]

This experiment in rats was designed to investigate the effect and mechanism of nitric oxide (NO) in the induction of hypoxic pulmonary hypertension. The plasma concentrations of NO in normal controls and in the 1-, 2- and 3-week hyporemic ventilation groups were measured. The hemodynamic and pathological changes were observed in rats of the 2-week group after bolus injection of L-Arginine and NG-nitro-L-arginine. The results showed that NO concentrations of the 1-2- and 3-week groups were 5 +/- 2.67 mumol/L 2.1 +/- 0.41 mumol/L and 0.5 +/- 0.16 mumol/L respectively, which were significantly lower than the control group's 6.73 +/- 1.83 mumol/L (P < 0.05). Bolus injection of L-Arginine 100 mg.kg-1.d-1 could relieve chronic hypoxic pulmonary hypertension and decrease the thickening of pulmonary arteries, but L-NNA could antagonize the effect of L-Arginine. This experiment demonstrates that chronic hypoxemia may decrease the release of NO and result in pulmonary hypertension. L-Arginine may be used to relieve pulmonary hypertension, but L-NNA may antagonize the effect of L-Arginine.