Nitrosyl hemoglobin in blood of normoxic and hypoxic sheep during nitric oxide inhalation.

Content Provider	Semantic Scholar
Author	Takahashi, Yumi Kobayashi, Hirosuke Tanaka, Naohiko Sato, Tetsuya Takizawa, Naosada Tomita, Toshiaki
Copyright Year	1998
Abstract	During nitric oxide (NO) inhalation therapy, NO combines with deoxyhemoglobin to form nitrosyl hemoglobin (HbNO). We used electron spin resonance (ESR) spectroscopy to measure HbNO in arterial and mixed venous blood of normoxic and hypoxic sheep during NO inhalation. Our aim was to quantitatively measure HbNO levels in the blood during NO inhalation, because large amounts of HbNO reduce the oxygen capacity of blood, particularly in hypoxia. Another aim was to investigate the transfer of exogenous NO to the alpha-heme iron of hemoglobin. Thirteen sheep were anesthetized with pentobarbital sodium, and 60 parts per million (ppm) NO were administered for 1 h in the presence of normoxia and hypoxia. Two-way analysis of variance revealed that the HbNO level was dependent on the oxygen level (normoxia vs. hypoxia) and NO inhalation, and there was a significant negative correlation between the HbNO level and arterial O2 saturation (SaO2). Although the HbNO level increased during NO inhalation in hypoxia, the HbNO level at SaO2 > 60% was < 11 mumol/l monomer hemoglobin (0.11% of total 10 mmol/l monomer hemoglobin). The peak of the HbNO ESR spectrum in arterial blood is located in almost the same position in mixed venous blood with an asymmetric HbNO signal, indicating that the NO in beta-heme HbNO molecules had been transferred to alpha-heme molecules. The three-line hyperfine structure of HbNO on ESR spectra was distinct in venous blood in hypoxia during NO inhalation, indicating pentacoordinate alpha-NO heme formation in hypoxic blood. In conclusion, the amount of HbNO during 60 ppm NO inhalation did not considerably reduce the oxygen capacity of the blood even in the presence of hypoxia, and the NO of HbNO was transferred to the alpha-heme iron of hemoglobin, forming pentacoordinate alpha-NO heme in mixed venous blood in hypoxia.
Starting Page	5667
Ending Page	5669
Page Count	3
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://ajpheart.physiology.org/content/ajpheart/274/1/H349.full.pdf
PubMed reference number	9458886v1
Volume Number	274
Issue Number	1
Part	2
Journal	The American journal of physiology
Language	English
Access Restriction	Open
Subject Keyword	Chorionic Gonadotropin, beta Subunit, Human Deoxyhemoglobin measurement Electron Spin Resonance Spectroscopy Heme Iron Hypoxia Inhalation Dosing Unit Inspiration function Millimole per Liter Nitric Oxide Oxygen Capacity Measurement Oxygen saturation measurement Pentobarbital Sodium Sample Variance heme biosynthetic process hemoglobin A, glycosylated-nitric oxide complex monomer part per million (ppm)
Content Type	Text
Resource Type	Article