Document Detail

Differences in tail vascular bed reactivity in rats with and without heart failure following myocardial infarction.
MedLine Citation:
PMID:  15561797     Owner:  NLM     Status:  MEDLINE    
Myocardial infarction (MI) was induced in rats by coronary ligation to compare changes in vascular reactivity from animals that developed heart failure (InfHF) with those that did not (Inf). Infarct size was similar in both groups. In vitro preparations of tail vascular bed were used to investigate the vascular responses to acetylcholine, sodium nitroprusside, and phenylephrine. Acetylcholine-induced relaxation was impaired in the Inf group (53 +/- 2%, n = 6) when compared with Sham (80 +/- 2%, n = 6, P < 0.05). The maximal response (E(max)) to phenylephrine increased in the Inf group (423 +/- 10 mm Hg, n = 9, P < 0.01) and decreased in InfHF (279 +/- 10 mm Hg, n = 7, P < 0.05) when compared with Sham (319 +/- 11 mm Hg, n = 8). Regardless of endothelial integrity, E(max) to phenylephrine increased in the Inf, nitro-l-arginine methyl ester, and indomethacin groups. An increased release of a prostanoid vasodilator was detected in the Inf group. Differently, the InfHF group presented a reduction of the E(max) to phenylephrine and an increment of nitric oxide release. This study demonstrates that MI without heart failure impairs endothelium-dependent relaxation and increases the reactivity to phenylephrine. This increase seems to involve a muscular component. The endothelium participates with an increased release of a vasodilator prostanoid, possibly to compensate the increased smooth muscle response. When heart failure follows MI, the reactivity to phenylephrine decreases, possibly due to an increased nitric oxide release.
Raquel Binda Pereira; Carmem Luíza Sartório; Dalton Valentim Vassallo; Ivanita Stefanon
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Publication Detail:
Type:  Journal Article     Date:  2004-11-23
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  312     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  2005 Mar 
Date Detail:
Created Date:  2005-02-16     Completed Date:  2005-04-05     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1321-5     Citation Subset:  IM    
Department of Physiological Sciences, Rua Leocádia Pedra dos Santos, 15, Enseada do Suá-Vitória, ES, Brazil.
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MeSH Terms
Dose-Response Relationship, Drug
Heart Failure / physiopathology*
Indomethacin / pharmacology
Myocardial Infarction / physiopathology*
NG-Nitroarginine Methyl Ester / pharmacology
Nitric Oxide / physiology
Phenylephrine / pharmacology
Rats, Wistar
Tail / blood supply
Vasoconstriction / drug effects*
Reg. No./Substance:
10102-43-9/Nitric Oxide; 50903-99-6/NG-Nitroarginine Methyl Ester; 53-86-1/Indomethacin; 59-42-7/Phenylephrine

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