Role of endothelium in control of forearm blood flow in patients with heart failure.
We studied the role of endothelium in control of forearm blood flow during reactive and exercise hyperemia in patients with heart failure as well as in normal subjects. First, endothelium-dependent forearm vasodilation in response to acetylcholine (ACh), substance P, and endothelium-independent forearm vasodilation in response to sodium nitroprusside (SNP) were examined in patients with heart failure and in normal subjects. Endothelium-dependent forearm vasodilation in response to ACh but not to substance P was impaired in patients with heart failure. Endothelium-independent forearm vasodilation to SNP was also preserved in patients with heart failure. Second, the role of nitric oxide (NO) in reactive hyperemia and exercise hyperemia was examined in normal subjects using NG-monomethyl-L-arginine (L-NMMA), a blocker of NO synthesis. Results suggest that NO plays a minimal role in peak reactive hyperemia and exercise hyperemia in normal human forearm vessels. Finally, we determined if L-arginine, a precursor of NO, improves impaired endothelium-dependent vasodilation due to ACh and reactive and exercise hyperemia in patients with heart failure. L-Arginine augmented impaired ACh-induced vasodilation as well as reactive and exercise hyperemia in patients with heart failure. Our results suggest that defective endothelial function may contribute to abnormal control of forearm blood flow in patients with heart failure.
Takeshita
A
A
Research Institute of Angiocardiology, Kyushu University School of Medicine, Fukuoka, Japan.
Hirooka
Y
Y
Imaizumi
T
T
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000368:Aged; D001120:Arginine / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology*; D005542:Forearm / Q000098:blood supply*; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology; D014666:Vasomotor System / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000494:pharmacology
D014665:Vasodilator Agents; D009599:Nitroprusside; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D013373:Substance P; D001120:Arginine; D000109:Acetylcholine