Document Detail


Exposure to low mercury concentration in vivo impairs myocardial contractile function.
MedLine Citation:
PMID:  21723307     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Increased cardiovascular risk after mercury exposure has been described but cardiac effects resulting from controlled chronic treatment are not yet well explored. We analyzed the effects of chronic exposure to low mercury concentrations on hemodynamic and ventricular function of isolated hearts. Wistar rats were treated with HgCl(2) (1st dose 4.6μg/kg, subsequent dose 0.07μg/kg/day, im, 30days) or vehicle. Mercury treatment did not affect blood pressure (BP) nor produced cardiac hypertrophy or changes of myocyte morphometry and collagen content. This treatment: 1) in vivo increased left ventricle end diastolic pressure (LVEDP) without changing left ventricular systolic pressure (LVSP) and heart rate; 2) in isolated hearts reduced LV isovolumic systolic pressure and time derivatives, and β-adrenergic response; 3) increased myosin ATPase activity; 4) reduced Na(+)-K(+) ATPase (NKA) activity; 5) reduced protein expression of SERCA and phosphorylated phospholamban on serine 16 while phospholamban expression increased; as a consequence SERCA/phospholamban ratio reduced; 6) reduced sodium/calcium exchanger (NCX) protein expression and α-1 isoform of NKA, whereas α-2 isoform of NKA did not change. Chronic exposure for 30days to low concentrations of mercury does not change BP, heart rate or LVSP but produces small but significant increase of LVEDP. However, in isolated hearts mercury treatment promoted contractility dysfunction as a result of the decreased NKA activity, reduction of NCX and SERCA and increased PLB protein expression. These findings offer further evidence that mercury chronic exposure, even at small concentrations, is an environmental risk factor affecting heart function.
Authors:
Lorena Barros Furieri; Mirian Fioresi; Rogério Faustino Ribeiro Junior; María Visitación Bartolomé; Aurélia Araújo Fernandes; Victoria Cachofeiro; Vicente Lahera; Mercedes Salaices; Ivanita Stefanon; Dalton Valentim Vassallo
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-6-24
Journal Detail:
Title:  Toxicology and applied pharmacology     Volume:  -     ISSN:  1096-0333     ISO Abbreviation:  -     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-7-4     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0416575     Medline TA:  Toxicol Appl Pharmacol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011. Published by Elsevier Inc.
Affiliation:
Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil.
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