Linked Life Data

17516466

Source:http://linkedlifedata.com/resource/pubmed/id/17516466

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-2-13
pubmed:abstractText
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.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0952-3480
pubmed:author
pubmed:issnType
Print
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
101-10
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Alterations in inorganic phosphate in mouse hindlimb muscles during limb disuse.
pubmed:affiliation
Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural