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975877 
Journal Article 
Abstract 
Nitric oxide does escape from red blood cell - Experimental evidence 
Piknova, B; Schechter, AN 
2008 
Yes 
Free Radical Biology and Medicine
ISSN: 0891-5849
EISSN: 1873-4596 
45 
Suppl. 
S116-S116 
English 
WOS:000260867900332 
is part of a larger document 3452652 SFRBM's 15th Annual Meeting: Program and Abstracts
Nitric oxide (NO•) regulates a wide array of biological processes and its deficit likely contributes to the severity of some diseases. Discovery of nitrite reductase activity of heme-containing proteins, especially case of deoxyHb, opened the path to the speculations about red blood cell (RBC) as the possible alternative source of NO•, in addition to “classical” L-arginine/NOS pathway. in clinical studies nitrite infusions have led to vasodilatation, and nitrite infusion based therapies to correct NO• deficits are currently under consideration. However, oxyHb also rapidly reacts with NO• and nitrite, and the final products of both oxidative reaction chains are nitrate and metHb. As oxyHb is the prevailing hemoglobin species in blood, main question then is if any of NO• from deoxyHb/nitrite reaction in RBC can escape from the RBC into plasma compartment. So far, this possibility was evaluated mainly in theoretical plane and the general prevailing opinion is that RBC would act as a sink/black hole for NO•. We experimentally tested the hypothesis that NO• produced by nitrite reductase activity of deoxyHb can be liberated from RBC. Measurements were done for different hematocrits and different hemoglobin oxygen saturations. We demonstrate that, despite the large excess of oxyHb, small but measurable quantities of free NO• (in pM /subpM range) are liberated into the surrounding solution at all oxygen saturations and total amount of measured NO• inversely correlates with oxygen saturation. We consider our results to be a direct evidence that nitrite causes vasodilatation directly through nitrite reduction to NO• via deoxyHb and not by some other RBC-related mechanisms. 
Society for Free Radical Biology and Medicine 15th Annual Meeting 
Indianapolis, IN 
November 19-23, 2008