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PubMed · 15596693

Prolonged nitric oxide inhalation during recovery from chronic hypoxia does not decrease nitric oxide-dependent relaxation in pulmonary arteries.

Junko Maruyama·Bao Hua Jiang·Kazuo Maruyama·Masao Takata·Katsuyuki Miyasaka
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Abstract

STUDY OBJECTIVE: To investigate the effects of long-term nitric oxide (NO) inhalation on the recovery process of right ventricular hypertrophy (RVH) and functional alterations in the NO-cyclic guanosine monophosphate (cGMP) relaxation pathway in rat conduit pulmonary arteries (PAs) in established chronic hypoxic pulmonary hypertension. MATERIALS AND METHODS: A total of 35 rats were exposed to chronic hypobaric hypoxia (380 mm Hg, 10% oxygen), and 39 rats were exposed to air for 10 days. Both groups were then exposed to 3 or 10 days of NO 10 ppm, NO 40 ppm, or air (control groups for each NO concentration), resulting in a total of 16 groups. Acetylcholine- and sodium nitroprusside (SNP)-induced relaxation were evaluated in precontracted PA rings. RVH was assessed by heart weight ratio of right ventricle to left ventricle plus septum. RESULTS: NO inhalation had no effect on either the regression of RVH or the recovery process of impaired relaxation induced by acetylcholine or SNP in a endothelium-intact hypertensive conduit extrapulmonary artery or intrapulmonary artery (IPA). In a normal endothelium-intact conduit IPA, 40 ppm NO inhalation for 10 days partially augmented SNP-induced relaxation, but not that induced by acetylcholine. CONCLUSION: Continuous NO inhalation did not affect the regression process of either established RVH or the impaired endogenous NO-cGMP relaxation cascade in a conduit PA in rats during the recovery period after chronic hypoxia.

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AcetylcholineAdministration, InhalationAnimalsChronic DiseaseCyclic GMPEndothelium, VascularEndothelium-Dependent Relaxing FactorsHypertension, PulmonaryHypertrophy, Right VentricularHypoxiaIn Vitro TechniquesMaleNitric OxideNitroprussidePulmonary ArteryRatsRats, WistarVasodilationVasodilator AgentsJournal ArticleResearch Support, Non-U.S. Gov't

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Junko Maruyama, Bao Hua Jiang, Kazuo Maruyama, Masao Takata, Katsuyuki Miyasaka. 2004. Prolonged nitric oxide inhalation during recovery from chronic hypoxia does not decrease nitric oxide-dependent relaxation in pulmonary arteries.. https://doi.org/10.1378/chest.126.6.1919

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