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CARDIOVASCULAR
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Volume 5, 2000, No 4 |
Endogenous
Nitric Oxide Regulates Heme Oxygenase/Carbon Monoxide System in Intrapulmonary
Arteries of Hypoxic Rats
G. Zhiliang, D. Junbao, Z. Heping, Q. Jianguang, T. Chaoshu
The study aimed to investigate the regulation of heme oxygenase/carbon monoxide system of pulmonary arteries by endogenous nitric oxide in hypoxic rats so as to explore the regulatory mechanism responsible for hypoxic pulmonary vascular structural remodeling. Twenty-one rats were randomly divided into three groups: normoxia group, hypoxia group and hypoxia +L-NAME group. Immunohistochemistry technique was used to assess the abundance and localization of heme oxygenase-1 in pulmonary arterial smooth muscle cells. At the same time the levels of carbon monoxide in plasma and lung tissue homogenates were detected by spectrophotometer. The expression of heme oxygenase-1 by pulmonary arteries smooth muscle cells of hypoxic rats increased significantly compared to that in normoxic rats (P < 0.01). However, when L-NAME was used, expression of heme oxygenase-1 by pulmonary artery smooth muscle cells of hypoxic rats decreased significantly compared to that in rats of hypoxia group (P < 0.01). The levels of carbon monoxide in plasma and lung tissue homogenates of hypoxia rats also increased significantly in hypoxic rats as compared to those of normoxic rats (P < 0.01). But they were markedly reduced in rats of hypoxia +L-NAME group compared to hypoxia group (P < 0.01). The results suggest that endogenous nitric oxide might regulate pulmonary circulation via carbon monoxide pathway under hypoxia.
(CVE. 2000; 5 (4): 267-270)
Key words: nitric oxide, carbon monoxide, heme oxygenase, pulmonary hypertension
Prof.
Du Junbao, M.D.
Department of Pediatrics
First Hospital of Beijing Medical University
Beijing 100034
P. R. China
E-mail: junbaodu@ht.rol.cn.net
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