TY - JOUR
T1 - Endothelium-dependent relaxation in response to poly-L-arginine in canine coronary arteries. Implications about hyperpolarization as a mechanism of vasodilatation
AU - Evora, Paulo Roberto B.
AU - Pearson, Paul J.
AU - Rodrigues, Alfredo José
AU - Viaro, Fernanda
AU - Schaff, Hartzell V.
PY - 2003/6/1
Y1 - 2003/6/1
N2 - 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.
AB - 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.
KW - EDHF
KW - Endothelium
KW - Nitric oxide
KW - Poly-L-arginine
KW - Polycations
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U2 - 10.1590/s0066-782x2003000600005
DO - 10.1590/s0066-782x2003000600005
M3 - Article
C2 - 12856072
AN - SCOPUS:0141705522
SN - 0066-782X
VL - 80
SP - 621
EP - 630
JO - Arquivos brasileiros de cardiologia
JF - Arquivos brasileiros de cardiologia
IS - 6
ER -