Article: article from journal or magazin.
Neuronal nitric oxide synthase does not contribute to the modulation of pulmonary vascular tone in fetal lambs with congenital diaphragmatic hernia (nNOS in CDH lambs).
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
AIM: The aim of this study was to determine the presence of the neuronal nitric oxide synthase (nNOS) in near full-term lambs with congenital diaphragmatic hernia (CDH) and its role in the modulation of pulmonary vascular basal tone. METHODS: We surgically created diaphragmatic hernia on the 85th day of gestation. On the 135th, catheters were used to measure pulmonary pressure and blood flow. We tested the effects of 7-nitroindazole (7-NINA), a specific nNOS antagonist and of N-nitro-L-arginine (L-NNA), a nonspecific nitric oxide synthase antagonist. In vitro, we tested the effects of the same drugs on isolated pulmonary vessels. The presence of nNOS protein in the lungs was detected by Western blot analysis. RESULTS: Neither 7-NINA nor L-NNA modified pulmonary vascular basal tone in vivo. After L-NNA injection, acetylcholine (ACh) did not decrease significantly pulmonary vascular resistance (PVR). In vitro, L-NNA increased the cholinergic contractile-response elicited by electric field stimulation (EFS) of vascular rings from lambs with diaphragmatic hernia. CONCLUSION: We conclude that nNOS protein is present in the lungs and pulmonary artery of near full-term lamb fetuses with diaphragmatic hernia, but that it does not contribute to the reduction of pulmonary vascular tone at birth
Animals, Blood Pressure/drug effects, Blotting, Western, Disease Models, Animal, Enzyme Inhibitors/pharmacology, Fetus/drug effects, Fetus/enzymology, Gestational Age, Heart Rate/drug effects, Hernia, Diaphragmatic/congenital, Hernia, Diaphragmatic/enzymology, Lung/blood supply, Lung/drug effects, Nitric Oxide Synthase Type I/antagonists & inhibitors, Nitric Oxide Synthase Type I/metabolism, Organ Culture Techniques, Pulmonary Artery/drug effects, Pulmonary Artery/enzymology, Pulmonary Circulation/drug effects, Sheep, Vascular Resistance/drug effects
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