Relaxamento dependente do endotélio causado pela poli-L-arginina. Implicações sobre a hiperpolarização como mecanismo de vasodilatação

Translated title of the contribution: Endothelium-dependent relaxation in response to poly-L-arginine in canine coronary arteries. Implications about hyperpolarization as a mechanism of vasodilatation

Paulo Roberto B. Evora, Paul J. Pearson, Alfredo José Rodrigues, Fernanda Viaro, Hartzell V. Schaff

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Objective - To study the mechanism by which poly-L-arginine mediates endothelium-dependent relaxation. Methods - Vascular segments with and without endothelium were suspended in organ chambers filled with control solution maintained at 37°C and bubbled with 95% O2/5% CO2. Used drugs: indomethacin, acetycholine, EGTA, glybenclamide, ouabain, poly-L-arginine, methylene blue, NG-nitro-L-arginine, and verapamil and NG-monomethyl-L-arginine. Prostaglandin F2a and potassium chloride were used to contract the vascular rings. Results - Poly-L-arginine (10-11 to 10-7 M) induced concentration-dependent relaxation in coronary artery segments with endothelium. The relaxation to poly-L-arginine was attenuated by ouabain, but was unaffected by glybenclamide. L-NOARG and oxyhemoglobin caused attenuation, but did not abolish this relaxation. Also, the relaxations was unaffected by methylene blue, verapamil, or the presence of a calcium-free bathing medium. The endothelium-dependent to poly-L-arginine relaxation was abolished only in vessels contracted with potassium chloride (40 mM) in the presence of L-NOARG and indomethacin. Conclusion - These experiments indicate that poly-L-arginine induces relaxation independent of nitric oxide.

Translated title of the contributionEndothelium-dependent relaxation in response to poly-L-arginine in canine coronary arteries. Implications about hyperpolarization as a mechanism of vasodilatation
Original languagePortuguese
Pages (from-to)621-630
Number of pages10
JournalArquivos brasileiros de cardiologia
Volume80
Issue number6
DOIs
StatePublished - Jun 1 2003

Keywords

  • EDHF
  • Endothelium
  • Nitric oxide
  • Poly-L-arginine
  • Polycations

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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