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Impaired vascular responses to relaxin in diet-induced overweight female rats.
MedLine Citation:
PMID:  22174401     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Relaxin mediates renal and mesenteric vascular adaptations to pregnancy by increasing endothelium-dependent vasodilation and compliance, and decreasing myogenic reactivity. Diet-induced overweight and obesity are associated with impaired endothelial dysfunction and vascular remodeling leading to a reduction in arterial diameter. In this study, we tested the hypothesis that local vascular responses to relaxin are impaired in diet-induced overweight female rats on a high-fat cafeteria-style diet for 9 weeks. Rats were chronically infused with either relaxin or placebo for 5 days and vascular responses were measured in isolated mesenteric arteries and the perfused kidney. Diet-induced overweight significantly increased sensitivity to phenylephrine (by 17%) and vessel wall thickness, reduced renal perfusion flow (RPFF, by 16%), but did not affect flow-mediated vasodilation, myogenic reactivity and vascular compliance. In the normal weight rats, relaxin treatment significantly enhanced flow-mediated vasodilation (2.67 fold), decreased myogenic reactivity, and reduced sensitivity to phenylephrine (by 28%), but had no effect on compliance or RPFF. NO blockade by L-NAME diminished most relaxin-mediated effects. In diet-induced overweight rats, the vasodilator effects of relaxin were markedly reduced for flow-mediated vasodilation, sensitivity to phenylephrine and myogenic response, as compared to the normal diet rats, mostly persistent under L-NAME. Our data demonstrate that some of the vasodilator responses to in vivo relaxin administration are impaired in isolated mesenteric arteries and the perfused kidney in diet-induced overweight female rats. This does not result from a decrease in Rxfp1 (relaxin family peptide receptor) expression but is likely to result from downstream disruption to endothelial-dependent mechanisms in diet-induced overweight animals.
Authors:
Joris van Drongelen; Arianne van Koppen; Jeanne Pertijs; Jonathan H Gooi; Laura J Parry; Fred C G J Sweep; Frederik K Lotgering; Paul Smits; Marc Ea Spaanderman
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-12-15
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  -     ISSN:  1522-1601     ISO Abbreviation:  -     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2011-12-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
1Radboud University Nijmegen Medical Centre.
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