Analysis of oxygen and NADH fluorescence to determine critical O2 (O 2) tension in skeletal muscle in vivo and in vitro

K. N. Richmond, S. J. Burnite, P. C. Johnson, Ron Lynch

Research output: Contribution to journalArticle

Abstract

When muscle work and metabolism increase, blood flow increases to maintain supply of O 2 and other substrates. To explain matching of blood flow to metabolism, it has been proposed that vasodilating metabolic end products such as adenosine, produced when mitochondria in muscle become O 2 limited, act at arterioles to increase blood flow. However, blood flow is regulated at O 2 tensions at least 10 fold higher than the Km of cytochrome oxidase for O 2 in isolated mitochondria. Mitochondrial metabolic state (NADH fluorescence) and O 2 tension (porphyrin phosphorescence) were measured in exteriorized spinotrapezius muscle and isolated myocytes to determine if the O 2 sensitivity for isolated mitochondria is different than that of mitochondria in intact cells or tissue In isolated cells NADH fluorescence was verified as a good indicator of mitochondrial metabolic state which, similar to isolated mitochondria, became inhibited near 1 mmHg O 2. In intact muscle, the O 2 sensitivity was slightly higher than in isolated cells (2.4 mmHg, n=12). However, mean PO 2 measured in muscle is approximately 20 mmHg which is too high for proposed metabolic feedback mechanism to operate. These findings suggest that vasodilator products of anaerobic metabolism are not involved in blood flow regulation under normal working conditions, but only in highly O 2 deficient or non-oxidative tissue regions.

Original languageEnglish (US)
JournalFASEB Journal
Volume11
Issue number3
StatePublished - 1997

Fingerprint

Mitochondria
NAD
blood flow
Muscle
skeletal muscle
Skeletal Muscle
mitochondria
Blood
Fluorescence
fluorescence
Oxygen
oxygen
muscles
Metabolism
Muscles
phosphorescence
Tissue
Muscle Mitochondrion
Anaerobiosis
Phosphorescence

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology

Cite this

Analysis of oxygen and NADH fluorescence to determine critical O2 (O 2) tension in skeletal muscle in vivo and in vitro. / Richmond, K. N.; Burnite, S. J.; Johnson, P. C.; Lynch, Ron.

In: FASEB Journal, Vol. 11, No. 3, 1997.

Research output: Contribution to journalArticle

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