Role of Nitric Oxide (No) on Free Radical-Induced Pulmonary Vasoconstriction in Newborn Piglets. 62

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Figure 1

Aim: To test whether NO is involved in free radical-induced pulmonary vasoconstriction. Subjects: twenty-six newborn piglets(1-3 d). Interventions: Ventilated newborn piglets were assigned to 4 groups: The SNP+XO group (n=7) received 10 mL/kg of hypoxanthine (Hx, 10 mmol/L), xanthine oxidase (XO) (1.5 U/kg) and sodium nitroprusside (SNP, 10 ug/kg/min) i.v.; the XO group (n=7) only received Hx and XO i.v.; the APL group (n=5) received 50 mg/kg of allopurinol i.v. prior to XO, and the control group (n=6) received only same volume of saline i.v. Results: In the XO group, pulmonary vascular resistance (PVR) increased significantly 20, 30 and 40 min after XO i.v., and pulmonary arterial pressure increased significantly at 20 min after XO i.v. (p<0.05). In contrast, no changes were seen in the SNP+XO, APL or control groups .Conclusion: Free radical-induced pulmonary vasoconstriction in newborn piglets may be associated with inhibition of NO synthase.