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Updated: May 11, 2026
07:13
Platelet-based Detection of Nitric Oxide in Blood by Measuring VASP Phosphorylation
Published on: January 7, 2019
Nitrite reduction to nitric oxide by deoxyhemoglobin vasodilates the human circulation
Kenyatta Cosby1, Kristine S Partovi, Jack H Crawford
1Cardiovascular Branch, National Heart, Lung and Blood Institute, National Institutes of Health, 10 Center Drive, Building 10, Room 7B15 Bethesda, Maryland 20892, USA.
Nature Medicine
|November 5, 2003
Summary
Nitrite serves as a major nitric oxide (NO) reservoir. Hemoglobin acts as a nitrite reductase, converting nitrite to NO, which helps dilate blood vessels, especially during low oxygen conditions.
Area of Science:
- Physiology
- Biochemistry
- Cardiovascular Science
Background:
- Nitrite anions are the primary vascular reservoir for nitric oxide (NO).
- Physiological mechanisms are required to convert nitrite to NO for vasodilation.
- The role of nitrite in NO bioavailability and vasodilation requires further elucidation.
Purpose of the Study:
- To investigate the vasodilator properties of nitrite in the human forearm.
- To explore the mechanisms underlying nitrite bioactivation.
- To determine the role of hemoglobin in nitrite reduction and NO formation.
Main Methods:
- Infusion of nitrite into the human brachial artery.
- Measurement of forearm blood flow during rest and exercise.
- Assessment of NO-modified hemoglobin formation.
- In vitro studies using rat aortic rings and deoxygenated erythrocytes.
Main Results:
- Nitrite infusions increased forearm blood flow, independent of NO synthase inhibition.
- Nitrite administration led to the formation of NO-modified hemoglobin.
- Hemoglobin's nitrite reductase activity was linked to deoxygenation and hypoxia.
- Nitrite bioactivation and vasodilation were observed in rat aortic rings.
Conclusions:
- Nitrite is a significant source of bioavailable NO.
- Hemoglobin possesses nitrite reductase activity, converting nitrite to NO.
- This hemoglobin-mediated nitrite reduction contributes to hypoxic vasodilation.
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