Document Detail


Gestational Hypoxia Increases Reactive Oxygen Species and Inhibits Steroid Hormone-Mediated Upregulation of Ca2+-Activated K+ Channel Function in Uterine Arteries.
MedLine Citation:
PMID:  24866137     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Gestational hypoxia inhibits steroid hormone-induced upregulation of Ca(2+)-activated K(+) (KCa) channel activities in uterine arteries. We tested the hypothesis that increased reactive oxygen species play an important role in hypoxia-mediated inhibition of KCa channel activities. Uterine arteries were isolated from nonpregnant (nonpregnant uterine artery) and near-term (≈142-145 day) pregnant (pregnant uterine artery) sheep maintained at either sea level or high altitude (3820 m, Pao2: 60 mm Hg) for 110 days. In pregnant uterine arteries, hypoxia significantly decreased large conductance channel opener NS1619- and small conductance channel opener NS309-induced relaxations, which were partially restored by reactive oxygen species inhibitor N-acetylcysteine (NAC). NAC significantly increased large conductance KCa but not small conductance KCa current densities in uterine arterial smooth muscle cells in pregnant animals acclimatized to high altitude. The NAC-sensitive component of small conductance KCa-induced relaxations was diminished in endothelium-denuded arteries. In nonpregnant uterine arteries, NS1619- and NS309-induced relaxations were diminished compared with those in pregnant uterine arteries. Treatment of nonpregnant uterine arteries with 17β-estradiol and progesterone for 48 hours increased small conductance KCa type 3 protein abundance and NS1619- and NS309-induced relaxations, which were inhibited by hypoxia. This hypoxia-mediated inhibition was reversed by NAC. Consistently, steroid hormone treatment had no significant effects on large conductance KCa current density in nonpregnant uterine arteries of hypoxic animals in the absence of NAC but significantly increased it in the presence of NAC. These results suggest an important role of hypoxia-mediated reactive oxygen species in negatively regulating steroid hormone-mediated upregulation of KCa channel activity and adaptation of uterine vascular reactivity in pregnancy, which may contribute to the increased incidence of preeclampsia and fetal intrauterine growth restriction associated with gestational hypoxia.
Authors:
Ronghui Zhu; Xiaohui Huang; Xiang-Qun Hu; DaLiao Xiao; Lubo Zhang
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-5-27
Journal Detail:
Title:  Hypertension     Volume:  -     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2014 May 
Date Detail:
Created Date:  2014-5-28     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2014 American Heart Association, Inc.
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