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Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse.

Publication ,  Journal Article
Pathare, N; Vandenborne, K; Liu, M; Stevens, JE; Li, Y; Frimel, TN; Walter, GA
Published in: NMR Biomed
February 2008

Muscle disuse induces a wide array of structural, biochemical, and neural adaptations in skeletal muscle, which can affect its function. We recently demonstrated in patients with an orthopedic injury that cast immobilization alters the resting P(i) content of skeletal muscle, which may contribute to loss of specific force. The goal of this study was to determine the direct effect of disuse on the basal phosphate content in skeletal muscle in an animal model, avoiding the confounding effects of injury/surgery. (31)P and (1)H MRS data were acquired from the gastrocnemius muscle of young adult mice (C57BL6 female, n = 8), at rest and during a reversible ischemia experiment, before and after 2 weeks of cast immobilization. Cast immobilization resulted in an increase in resting P(i) content (75%; p < 0.001) and the P(i) to phosphocreatine (PCr) ratio (P(i)/PCr; 80%, p < 0.001). The resting concentrations of ATP, PCr and total creatine (PCr + creatine) and the intracellular pH were not significantly different after immobilization. During ischemia (30 min), PCr concentrations decreased to 54 +/- 2% and 52 +/- 6% of the resting values in pre-immobilized and immobilized muscles, respectively, but there were no detectable differences in the rates of P(i) increase or PCr depletion (0.55 +/- 0.01 mM min(-1) and 0.52 +/- 0.03 mM min(-1) before and after immobilization, respectively; p = 0.78). At the end of ischemia, immobilized muscles had a twofold higher phosphorylation potential ([ADP][P(i)]/[ATP]) and intracellular buffering capacity (3.38 +/- 0.54 slykes vs 6.18 +/- 0.57 slykes). However, the rate of PCr resynthesis (k(PCr)) after ischemia, a measure of in vivo mitochondrial function, was significantly lower in the immobilized muscles (0.31 +/- 0.04 min(-1)) than in pre-immobilized muscles (0.43 +/- 0.04 min(-1)). In conclusion, our findings indicate that 2 weeks of cast immobilization, independent of injury-related alterations, leads to a significant increase in the resting P(i) content of mouse skeletal muscle. The increase in P(i) with muscle disuse has a significant effect on the cytosolic phosphorylation potential during transient ischemia and increases the intracellular buffering capacity of skeletal muscle.

Duke Scholars

Published In

NMR Biomed

DOI

ISSN

0952-3480

Publication Date

February 2008

Volume

21

Issue

2

Start / End Page

101 / 110

Location

England

Related Subject Headings

  • Rest
  • Protons
  • Phosphorylation
  • Phosphocreatine
  • Phosphates
  • Nuclear Medicine & Medical Imaging
  • Muscular Atrophy
  • Muscle, Skeletal
  • Muscle Weakness
  • Mitochondria, Muscle
 

Citation

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Pathare, N., Vandenborne, K., Liu, M., Stevens, J. E., Li, Y., Frimel, T. N., & Walter, G. A. (2008). Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse. NMR Biomed, 21(2), 101–110. https://doi.org/10.1002/nbm.1162
Pathare, Neeti, Krista Vandenborne, Min Liu, Jennifer E. Stevens, Ye Li, Tiffany N. Frimel, and Glenn A. Walter. “Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse.NMR Biomed 21, no. 2 (February 2008): 101–10. https://doi.org/10.1002/nbm.1162.
Pathare N, Vandenborne K, Liu M, Stevens JE, Li Y, Frimel TN, et al. Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse. NMR Biomed. 2008 Feb;21(2):101–10.
Pathare, Neeti, et al. “Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse.NMR Biomed, vol. 21, no. 2, Feb. 2008, pp. 101–10. Pubmed, doi:10.1002/nbm.1162.
Pathare N, Vandenborne K, Liu M, Stevens JE, Li Y, Frimel TN, Walter GA. Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse. NMR Biomed. 2008 Feb;21(2):101–110.
Journal cover image

Published In

NMR Biomed

DOI

ISSN

0952-3480

Publication Date

February 2008

Volume

21

Issue

2

Start / End Page

101 / 110

Location

England

Related Subject Headings

  • Rest
  • Protons
  • Phosphorylation
  • Phosphocreatine
  • Phosphates
  • Nuclear Medicine & Medical Imaging
  • Muscular Atrophy
  • Muscle, Skeletal
  • Muscle Weakness
  • Mitochondria, Muscle