Doctoral Dissertations
Muscle metabolism in dog skeletal muscle during fatiguing work with altered arterial oxygen tensions
Date of Award
8-1985
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Zoology
Major Professor
Hugh Welch
Committee Members
Edward T. Howley, Roland Bagby, Michael Sims
Abstract
These experiments were conducted to determine whether changes in arterial O2 tension are related to changes in muscle metabolism during fatiguing contractions. Arterial and venous circulation to the gastrocnemius muscle (n=8) was isolated and the calcanean tendon was attached to a force transducer. Each muscle was electrically stimulated through the sciatic nerve for three 2-min periods of fatiguing contractions separated by 8 min of rest. The arterial O2 tensions were altered for each work period (mean P O2 =44, 72, 391 Torr). Arterial and venous samples were drawn to measure lactate, O2 and C O2 concentrations (Van Slyke analysis) and [H+] — while muscle biopsies were taken to measure muscle [H+] (homogenate method) and lactate. Fatigue was evaluated as the decline in tension from peak initial tension. At rest, arterial [H+] was significantly different (p < 0.05) among treatments (low arterial O2 tension=39 nM ± 1 SE, high arterial O2 tension=47 ± 2). At the end of the contraction periods, values (mean ± SE) were significantly different (p < 0.05) between the low arterial O2 tension and the high for flow (84± 6 vs. 70 ± 8 ml/100g per min), muscle lactate concentration (44 ± 10 vs. 26 ± 4 mmol/kg dry wt) and lactate release (122 ± 12 vs. 57 ± 14 umol/100g per min). Oxygen uptake and fatigue were not different among treatments during contractions. Muscle [H+] increased (work [H+] minus rest [H+]) to a significantly greater extent during low arterial O2 tensions as compared to high (p < 0.05).
I concluded that altering the arterial O2 tensions during fatiguing contractions induces changes in blood and muscle acid-base status and in muscle metabolism. The mechanisms for these alterations cannot be determined from this investigation. Although the rate of fatigue was not different among treatments in this study, I hypothesize that these changes in muscle metabolism may be responsible for performance differences measured during hypoxic and hyperoxic work.
Recommended Citation
Hogan, Michael C., "Muscle metabolism in dog skeletal muscle during fatiguing work with altered arterial oxygen tensions. " PhD diss., University of Tennessee, 1985.
https://trace.tennessee.edu/utk_graddiss/12570