The Main Action Pathway Of Nitric Oxide Diastolic Dog Pulmonary Vascular

Objectives: The aim of this study was based on the model of dog hypoxic pulmonary vasoconstriction to research whether nitric oxide is direct effect on pulmonary arteriole to reduce pulmonary artery pressure and discuss the possible action pathway.Methods: 16 male beagles, were randomly divided into two groups(8 among of these dogs was removed the one side of vagus nerve).Based on the model of hypoxic pulmonary vasoconstriction,Given a constant concentration of NO through the respiratory tract or the oxygenator of pulmonary circulation after the success of the animal systemic-lung bi-circulating model established. The mean pulmonary artery pressure and mean arterial pressure were continuously monitored. At the end of Each processing,we obtaining blood samples from left or right atrium. The experimental group of One side of Vagus nerve removed, after a month practice the experiment, the systemic-lung bi-circulating model was established, then blocked arteries which were into the left or right pulmonary artery, the other steps as well as the normal group.Results: Hypoxia can lead to pulmonary arterial pressure increased significantly compared with fundamental value(P<0.01).After inhalation of NO through the respiratory tract, the pulmonary arterial pressure restored to normal level(P<0.01). After inhalation of NO through the oxygenator of pulmonary circulation, the pulmonary arterial pressure was no obvious change(P>0.05). After removal of unilateral vagus nerve, the pulmonary arterial pressure of the both sides was not affected by hypoxia or inhalation of NO(P>0.05).Conclusions: The role of nitric oxide to reduce pulmonary artery pressure is through the vagus nerve way rather than direct effects on pulmonary arteriole.