Quantifying Human Resting Intramyocellular Oxygen Tension In Vivo

Presenter

Karan Srikrishna

Campus

UMass Amherst

Sponsor

Jane Kent, Department of Kinesiology, UMass Amherst

Schedule

Session 4, 2:30 PM - 3:15 PM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board A99, Campus Center Auditorium, Row 5 (A81-A100) [Poster Location Map]

Abstract

The proper functioning of cells relies significantly on the availability of oxygen. The partial pressure of oxygen (PO₂) in resting leg muscles has been shown to be 34 Torr, based on an observed myoglobin desaturation of 9%. However, this result has not been replicated or extended to other muscle groups. Additionally, the minimum acquisition time needed to determine an accurate PO₂ is not known. We hypothesize that 10 minutes of sample averaging will not be sufficient, as the previous study has utilized extended signal averaging (30 minutes) to record an accurate PO₂. Moreover, we speculate that there would be no difference in the PO₂ between the 20 and 30-minute periods of acquisition. We will measure PO₂ in the resting vastus lateralis muscle of 8 participants, using ¹H magnetic resonance spectroscopy, with three sample averages (10, 20, and 30 minutes). Scans (30 ms repetition time) will be acquired for 40 minutes total, followed by rapid inflation of a blood pressure cuff to occlude blood flow to the muscle for 10 minutes. During this occlusion, we will determine the maximal deoxymyoglobin (dMb) signal and use that to calculate its fractional saturation and PO₂: [PO₂ = P₅₀ (1-f_dmb / f_dmb)]. We will assume a P₅₀ (PO₂ of oxygen at which myoglobin is 50% saturated) of 2.39 Torr. To test our hypotheses, we will perform a one-way ANOVA to compare the PO₂ from the 10, 20 and 30 minute time averages. Post-hoc analyses will be pursued if a significant main effect is observed. 

Keywords

Intracellular oxygenation, Myoglobin desaturation, Muscle oxygen levels, Magnetic resonance spectroscopy, Resting muscle oxygenation

Research Area

Sports and Exercise Science + Physiology

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