Document Detail

Effects of oxygen tension and normalization pressure on endothelin-induced constriction of human placental chorionic plate arteries.
MedLine Citation:
PMID:  16202925     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: Fetoplacental blood vessels constrict in response to endothelin (ET-1) or reduced oxygen tension in the placental cotyledon perfused in vitro. In nonplacental resistance arteries, hypoxia and ET-1 induce constriction by promoting Ca2+ influx into smooth muscle through membrane ion channels, which include voltage-gated Ca2+ channels (VGCCs). We hypothesized that VGCCs are involved in ET-1-induced constriction of fetoplacental resistance vessels and that their contribution to constriction is enhanced at low oxygen tension. METHODS: Chorionic plate small arteries from term placentas were studied using parallel wire myography. Arteries were normalized at 0.9 of L(5.1 kPa) ("low stretch" approximately 25 mm Hg; approximating physiologic vascular pressure) or 0.9 of L(13.3 kPa) ("high stretch" approximately 42 mm Hg) and experiments performed at oxygen tensions of 156, 38, and 15 mm Hg. RESULTS: When chorionic plate arteries were normalized at low stretch, oxygen tension did not affect constriction to ET-1. Nifedipine (10(-4) M), a blocker of L-type VGCCs, inhibited ET-1 (EC80)-induced constriction to a similar extent at each oxygen tension (52% to 64% inhibition). In contrast, when arteries were normalized at high stretch, constriction to ET-1 was greater at 38 than at 156 or 15 mm Hg oxygen and nifedipine inhibition of ET-1-induced constriction was greater at 38 and 15 mm Hg than at 156 mm Hg oxygen. CONCLUSIONS: VGCCs and nifedipine-insensitive processes underlie the contractile response of chorionic plate arteries to ET-1 and their relative contribution to vasoconstriction is modulated by oxygen tension when vessels are normalized at high stretch. However, contrary to our hypothesis, the response of chorionic plate arteries to ET-1 is not modulated by oxygen when vessels are normalized at physiologic pressure.
Emma J Cooper; Mark Wareing; Susan L Greenwood; Philip N Baker
Related Documents :
19700345 - Effects of ventilatory mode during one-lung ventilation on intraoperative and postopera...
22022125 - A comparative study of slow and fast suryanamaskar on physiological function.
7658105 - Simultaneous laser doppler and transcutaneous oxygen tension measurements in claudicant...
17014665 - Long-term invasive measurement of subcutaneous oxygen partial pressure above the sacrum...
7324255 - Increased pulmonary vascular resistance during liquid ventilation.
1530045 - Physiologic baroreceptor activity in the fetal lamb.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the Society for Gynecologic Investigation     Volume:  12     ISSN:  1556-7117     ISO Abbreviation:  J. Soc. Gynecol. Investig.     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2005-10-05     Completed Date:  2006-04-13     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9433806     Medline TA:  J Soc Gynecol Investig     Country:  United States    
Other Details:
Languages:  eng     Pagination:  488-94     Citation Subset:  IM    
Maternal and Fetal Health Research Centre, St Mary's Hospital, The Medical School, University of Manchester, Manchester, UK.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Arteries / physiology
Calcium Channels / physiology*
Chorion / physiology
Endothelin-1 / physiology*
Oxygen / metabolism*
Placenta / blood supply*,  physiology
Vascular Resistance
Vasoconstriction / physiology*
Reg. No./Substance:
0/Calcium Channels; 0/Endothelin-1; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Molecular signaling through G-protein-coupled receptors and the control of intracellular calcium in ...
Next Document:  Inhibition of amino acid transport system a by interleukin-1beta in trophoblasts.