Document Detail

Regionalization of endothelium-dependent relaxation in the thoracic aorta of pregnant and nonpregnant guinea pigs.
MedLine Citation:
PMID:  7734656     Owner:  NLM     Status:  MEDLINE    
Regional variation in the response of the thoracic aorta to contractile agonists has previously been demonstrated. Since the net contractile response reflects the interaction between smooth muscle activation and the release of endothelial substances, we hypothesize that agonist-stimulated release of endothelium-derived nitric oxide (NO) also varies along the length of the thoracic aorta. The distribution of thoracic aorta estrogen receptors is also regionalized. Since pregnancy augments the release of endothelium-derived NO by acetylcholine (ACh) in some arterial beds, we further hypothesize that pregnancy enhances the stimulated release of NO from the thoracic aorta. Aortae were removed from nonpregnant and near term pregnant guinea pigs and cut into ring segments numbered sequentially proximal to distal. The rings were suspended at their optimal passive tension and submaximally contracted with prostaglandin F2 alpha. Endothelium-derived NO-dependent relaxation to ACh increased moving proximal to distal along the aorta independent of pregnancy and ACh relaxation was unaffected by pretreatment with physostigmine to inhibit cholinesterase. The magnitude of the relaxation to carbachol among the different segments was similar to ACh. Pregnancy decreased the ED50 for ACh of segments from the middle and distal segments of the thoracic aorta. Relaxation to the NO donor sodium nitroprusside and the nonreceptor-mediated endothelium-dependent relaxing agent A23187 was uniform along the length of the aorta and independent of pregnancy. These experiments demonstrate regional variation in the stimulated release of endothelium-derived NO in the guinea pig thoracic aorta which is increased by pregnancy.
A R Gregg; L P Thompson; J E Herrig; C P Weiner
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of vascular research     Volume:  32     ISSN:  1018-1172     ISO Abbreviation:  J. Vasc. Res.     Publication Date:    1995 Mar-Apr
Date Detail:
Created Date:  1995-06-06     Completed Date:  1995-06-06     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9206092     Medline TA:  J Vasc Res     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  106-11     Citation Subset:  IM    
Department of Obstetrics and Gynecology, University of Iowa College of Medicine, Iowa City 52242-1080, USA.
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MeSH Terms
Acetylcholine / pharmacology
Aorta, Thoracic / physiology*
Endothelium, Vascular / physiology
Guinea Pigs
Nitric Oxide / metabolism
Pregnancy, Animal / physiology*
Vasodilation / drug effects
Grant Support
Reg. No./Substance:
10102-43-9/Nitric Oxide; 51-84-3/Acetylcholine

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