| Acute lead-induced vasoconstriction in the vascular beds of isolated perfused rat tails is endothelium-dependent. | |
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MedLine Citation:
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PMID: 20396857 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Chronic lead exposure induces hypertension in humans and animals, affecting endothelial function. However, studies concerning acute cardiovascular effects are lacking. We investigated the effects of acute administration of a high concentration of lead acetate (100 microMu) on the pressor response to phenylephrine (PHE) in the tail vascular bed of male Wistar rats. Animals were anesthetized with sodium pentobarbital and heparinized. The tail artery was dissected and cannulated for drug infusion and mean perfusion pressure measurements. Endothelium and vascular smooth muscle relaxation were tested with acetylcholine (5 microg/100 microL) and sodium nitroprusside (0.1 microg/100 microL), respectively, in arteries precontracted with 0.1 microM PHE. Concentration-response curves to PHE (0.001-300 microg/100 microL) were constructed before and after perfusion for 1 h with 100 microMu lead acetate. In the presence of endothelium (E(+)), lead acetate increased maximal response (E(max)) (control: 364.4 +/- 36, Pb2(+): 480.0 +/- 27 mmHg; P < 0.05) and the sensitivity (pD(2); control: 1.98 +/- 0.07, 2.38 +/- 0.14 log mM) to PHE. In the absence of endothelium (E(-)) lead had no effect but increased baseline perfusion pressure (E(+): 79.5 +/- 2.4, E-: 118 +/- 2.2 mmHg; P < 0.05). To investigate the underlying mechanisms, this protocol was repeated after treatment with 100 microM L-NAME, 10 microM indomethacin and 1 microM tempol in the presence of lead. Lead actions on E(max) and pD(2) were abolished in the presence of indomethacin, and partially abolished with L-NAME and tempol. Results suggest that acute lead administration affects the endothelium, releasing cyclooxygenase-derived vasoconstrictors and involving reactive oxygen species. |
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Authors:
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E A Silveira; J H F Lizardo; L P Souza; I Stefanon; D V Vassallo |
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Publication Detail:
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Type: Journal Article Date: 2010-04-09 |
Journal Detail:
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Title: Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.] Volume: 43 ISSN: 1414-431X ISO Abbreviation: Braz. J. Med. Biol. Res. Publication Date: 2010 May |
Date Detail:
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Created Date: 2010-05-20 Completed Date: 2010-12-07 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8112917 Medline TA: Braz J Med Biol Res Country: Brazil |
Other Details:
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Languages: eng Pagination: 492-9 Citation Subset: IM |
Affiliation:
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Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, Brasil. ednasilveira@terra.com.br <ednasilveira@terra.com.br> |
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Endothelium, Vascular / drug effects*, physiology Male Organometallic Compounds / administration & dosage, pharmacology* Phenylephrine / pharmacology Rats Rats, Wistar Tail / blood supply* Vasoconstriction / drug effects* |
| Chemical | |
Reg. No./Substance:
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0/Organometallic Compounds; 301-04-2/lead acetate; 59-42-7/Phenylephrine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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