Comparative analysis of NMR and NIRS measurements of intracellular PO2 in human skeletal muscle

Tuan Khanh Tran, Napapon Sailasuta, Ulrike Kreutzer, Ralph Hurd, Youngran Chung, Paul Mole, Shinya Kuno, Thomas Jue

Research output: Contribution to journalArticlepeer-review

164 Scopus citations


1H NMR has detected both the deoxygenated proximal histidyl NδH signals of myoglobin (deoxyMb) and deoxygenated Hb (deoxyHb) from human gastrocnemius muscle. Exercising the muscle or pressure cuffing the leg to reduce blood flow elicits the appearance of the deoxyMb signal, which increases in intensity as cellular PO2 decreases. The deoxyMb signal is detected with a 45-s time resolution and reaches a steady-state level within 5 min of pressure cuffing. Its desaturation kinetics match those observed in the near-infrared spectroscopy (NIRS) experiments, implying that the NIRS signals are actually monitoring Mb desaturation. That interpretation is consistent with the signal intensity and desaturation of the deoxyHb proximal histidyl NδH signal from the β-subunit at 73 parts per million. The experimental results establish the feasibility and methodology to observe the deoxyMb and Hb signals in skeletal muscle, help clarify the origin of the NIRS signal, and set a stage for continuing study of O2 regulation in skeletal muscle.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number6 45-6
StatePublished - Jun 1999


  • Bioenergetics
  • Exercise
  • Hemoglobin
  • Myoglobin
  • Near-infrared spectroscopy
  • Oxygen

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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