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Author Notes:

Corresponding Author: Arshed A. Quyyumi, MD, FRCP, Professor of Medicine, Emory Clinical Cardiovascular Research Institute (ECCRI), Emory University, 1462 Clifton Road N.E. Suite 507, Atlanta GA 30322, Tel: (404) 727-3655, Fax: (404) 712-8785, aquyyum@emory.edu.

Disclosures: none

Subjects:

Research Funding:

National Institutes of Health Research Grant RO1 HL79115, and in part by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award no UL1TR000454 and the British Cardiovascular Society Research Fellowship, and the National Blood Foundation

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Hematology
  • Peripheral Vascular Disease
  • Cardiovascular System & Cardiology
  • African Americans
  • EDHF
  • exercise
  • nitric oxide
  • vasodilation
  • BRADYKININ-INDUCED VASODILATION
  • EXERCISE-INDUCED VASODILATION
  • FLOW-MEDIATED DILATATION
  • HUMAN FOREARM
  • RACIAL-DIFFERENCES
  • ESSENTIAL-HYPERTENSION
  • ETHNIC-DIFFERENCES
  • AFRICAN-AMERICANS
  • SMOOTH-MUSCLE
  • ARTERY

Differences in Vascular Nitric Oxide and Endothelium-Derived Hyperpolarizing Factor Bioavailability in African Americans and Whites

Tools:

Journal Title:

Arteriosclerosis, Thrombosis, and Vascular Biology

Volume:

Volume 34, Number 6

Publisher:

, Pages 1320-1327

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Objective-Abnormalities in nitric oxide (NO) bioavailability have been reported in blacks. Whether there are differences in endothelium-derived hyperpolarizing factor (EDHF) in addition to NO between blacks and whites and how these affect physiological vasodilation remain unknown. We hypothesized that the bioavailability of vascular NO and EDHF, at rest and with pharmacological and physiological vasodilation, varies between whites and blacks. Approach and Results-In 74 white and 86 black subjects without known cardiovascular disease risk factors, forearm blood flow was measured using plethysmography at rest and during inhibition of NO with NG-monomethyl-L-arginine and of K +Ca channels (EDHF) with tetraethylammonium. The reduction in resting forearm blood flow was greater with NG-monomethyl-L- arginine (P=0.019) and similar with tetraethylammonium in whites compared with blacks. Vasodilation with bradykinin, acetylcholine, and sodium nitroprusside was lower in blacks compared with whites (all P<0.0001). Inhibition with NG-monomethyl-L-arginine was greater in whites compared with blacks with bradykinin, acetylcholine, and exercise. Inhibition with tetraethylammonium was lower in blacks with bradykinin, but greater during exercise and with acetylcholine. Conclusions-The contribution to both resting and stimulus-mediated vasodilator tone of NO is greater in whites compared with blacks. EDHF partly compensates for the reduced NO release in exercise and acetylcholine-mediated vasodilation in blacks. Preserved EDHF but reduced NO bioavailability and sensitivity characterizes the vasculature in healthy blacks.

Copyright information:

© 2014 American Heart Association, Inc.

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