| Pregnancy downregulates actin polymerization and pressure-dependent myogenic tone in ovine uterine arteries. | |
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MedLine Citation:
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PMID: 20855655 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Pregnancy is associated with significantly decreased uterine vascular tone and increased uterine blood flow. The present study tested the hypothesis that the downregulation of actin polymerization plays a key role in reduced vascular tone of uterine arteries in the pregnant state. Uterine arteries were isolated from nonpregnant and near-term pregnant sheep. Activation of protein kinase C significantly increased the filamentous:globular actin ratio and contractions in the uterine arteries, which were inhibited by an actin polymerization inhibitor cytochalasin B. The basal levels of filamentous:globular actin were significantly higher in nonpregnant uterine arteries than those in near-term pregnant sheep. Prolonged treatment (48 hours) of nonpregnant sheep with 17β-estradiol (0.3 nmol/L) and progesterone (100.0 nmol/L) caused a significant decrease in the filamentous:globular actin. In accordance, the treatment of near-term pregnant sheep for 48 hours with an estrogen antagonist ICI 182 780 (10.0 μmol/L) and progesterone antagonist RU 486 (1.0 μmol/L) significantly increased the levels of filamentous:globular actin. Increased intraluminal pressure from 20 to 100 mm Hg resulted in an initial increase in uterine arterial diameter and vascular wall Ca(2+) concentrations, followed by a decrease in the diameter at a constant steady-state level of Ca(2+). Cytochalasin B blocked pressure-induced myogenic constrictions without effect on vascular wall Ca(2+) levels and eliminated the differences in pressure-dependent myogenic tone between nonpregnant sheep and near-term pregnant sheep. The results indicate a key role of actin polymerization in protein kinase C-induced myogenic contractions and suggest a novel mechanism of sex steroid hormone-mediated downregulation of actin polymerization underlying the decreased myogenic tone of uterine arteries in pregnancy. |
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Authors:
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Daliao Xiao; Xiaohui Huang; Shumei Yang; Lawrence D Longo; Lubo Zhang |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2010-09-20 |
Journal Detail:
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Title: Hypertension Volume: 56 ISSN: 1524-4563 ISO Abbreviation: Hypertension Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-10-21 Completed Date: 2010-11-10 Revised Date: 2011-11-01 |
Medline Journal Info:
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Nlm Unique ID: 7906255 Medline TA: Hypertension Country: United States |
Other Details:
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Languages: eng Pagination: 1009-15 Citation Subset: IM |
Affiliation:
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Center for Perinatal Biology, Department of Physiology and Pharmacology, Loma Linda University, School of Medicine, Loma Linda, CA 92350, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Actins
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metabolism* Analysis of Variance Animals Cytochalasin B / pharmacology Estradiol / pharmacology Estrogens / pharmacology Female Muscle, Smooth, Vascular / drug effects, physiology* Pregnancy Progesterone / pharmacology Progestins / pharmacology Protein Kinase C / metabolism Sheep Uterine Artery / drug effects, physiology* |
| Grant Support | |
ID/Acronym/Agency:
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HD31226/HD/NICHD NIH HHS; HL89012/HL/NHLBI NIH HHS; R01 HL082779-04/HL/NHLBI NIH HHS; R01 HL083966-04/HL/NHLBI NIH HHS; R01 HL083966-05/HL/NHLBI NIH HHS; R01 HL089012-03/HL/NHLBI NIH HHS; R01 HL089012-04/HL/NHLBI NIH HHS; S06GM073842/GM/NIGMS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Actins; 0/Estrogens; 0/Progestins; 14930-96-2/Cytochalasin B; 50-28-2/Estradiol; 57-83-0/Progesterone; EC 2.7.11.13/Protein Kinase C |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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