| Nitric oxide donors mediate vasodilation in human placental arteries partly through a direct effect on potassium channels. | |
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MedLine Citation:
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PMID: 16338463 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We have investigated the involvement of potassium channels in the NO-induced relaxation of small ET-1 precontracted arteries from placentas of normal pregnancies in the presence of the potassium channel modulating agents charybdotoxin, 4-AP, glibenclamide, TEA and the blocker of soluble guanylyl cyclase, ODQ, respectively. We have studied the effect of the NO-donor S-nitroso-N-acetylpenicillamine (SNAP) in vessels precontracted by different concentrations of potassium and we have also investigated the presence of BK(Ca) channels in placental arteries by immunohistochemistry and immunoblotting. Our results show that charybdotoxin, an inhibitor of large- and intermediate-conductance Ca(2+)-activated potassium channels, inhibits relaxation in placental arteries. In presence of both charybdotoxin and ODQ, the inhibition of relaxation was significantly stronger, which indicates that NO-induced relaxation of human placental arteries is partly mediated through cGMP, and partly through a direct effect on potassium channels of the BK(Ca) type. The NO-donor SNAP preferentially relaxes contractions induced by 75 mM K(+) as compared to 100 mM K(+). This effect profile is a unique feature of drugs acting by K(+) channel opening. The immunohistochemistry shows that BK(Ca) channels are located both in smooth muscle and in endothelium in placental arteries. |
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Authors:
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A Sand; E Andersson; G Fried |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Placenta Volume: 27 ISSN: 0143-4004 ISO Abbreviation: Placenta Publication Date: 2006 Feb-Mar |
Date Detail:
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Created Date: 2005-12-12 Completed Date: 2006-03-23 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8006349 Medline TA: Placenta Country: England |
Other Details:
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Languages: eng Pagination: 181-90 Citation Subset: IM |
Affiliation:
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Department of Women and Child Health, Division of Obstetrics and Gynaecology, Karolinska Institute and Hospital, S-171 76 Stockholm, Sweden. anna.sand@kbh.ki.se |
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Arteries / chemistry, drug effects Charybdotoxin / pharmacology Endothelin-1 / pharmacology Enzyme Inhibitors / pharmacology Female Humans Immunohistochemistry Nitric Oxide Donors / pharmacology* Oxadiazoles / pharmacology Placenta / blood supply*, chemistry, drug effects Potassium / pharmacology Potassium Channel Blockers / pharmacology Potassium Channels, Calcium-Activated / agonists, analysis, drug effects* Pregnancy Quinoxalines / pharmacology S-Nitroso-N-Acetylpenicillamine / pharmacology* Vasodilation* |
| Chemical | |
Reg. No./Substance:
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0/1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; 0/Endothelin-1; 0/Enzyme Inhibitors; 0/Nitric Oxide Donors; 0/Oxadiazoles; 0/Potassium Channel Blockers; 0/Potassium Channels, Calcium-Activated; 0/Quinoxalines; 115422-61-2/Charybdotoxin; 7440-09-7/Potassium; 79032-48-7/S-Nitroso-N-Acetylpenicillamine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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