Changes in signalling molecule levels in 10-day hindlimb immobilized rat muscles

Acta Physiol Scand. 2005 Feb;183(2):171-9. doi: 10.1111/j.1365-201X.2004.01395.x.


Aim: Hindlimb immobilization produces similar percentage decreases in muscle mass in the predominantly type I soleus and type II vastus lateralis muscles. Consequently we hypothesized that the percentage changes in potential regulatory molecules for atrophy would be similar in the two muscle fibre types.

Methods: Therefore, the purpose of the current study was to measure phosphorylated p38 MAPK and JNK, as well as the protein levels of p53, growth arrest and DNA damage-inducible 45 (GADD45), and full-length poly(ADP-ribose) polymerase (PARP) to determine whether their changes in expression in the soleus and vastus lateralis muscles were similar at 10th day of hindlimb immobilization in young rats.

Results: Unexpectedly, preferential increases in phosphorylation of p38 MAPK and JNK and in the protein levels of p53, GADD45, as well as decreases in full-length PARP occurred in the soleus muscle, while only p38 phosphorylation increased in the white portion of the vastus lateralis muscle at 10th day of hindlimb immobilization.

Conclusion: Taken together, these results are interpreted to suggest that some of regulatory processes or kinetics in the atrophy of type I and II muscle fibres during limb immobilization may differ at the 10th day of limb immobilization.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • DNA Damage
  • Hindlimb
  • Immobilization
  • Intracellular Signaling Peptides and Proteins
  • JNK Mitogen-Activated Protein Kinases / analysis
  • Male
  • Mitogen-Activated Protein Kinases / analysis*
  • Muscle Proteins / analysis*
  • Muscle, Skeletal / chemistry*
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / growth & development
  • Muscular Atrophy / metabolism
  • Phosphorylation
  • Poly(ADP-ribose) Polymerases / analysis
  • Proteins / analysis
  • Rats
  • Rats, Inbred F344
  • Tumor Suppressor Protein p53 / analysis
  • p38 Mitogen-Activated Protein Kinases / analysis


  • GADD45 protein
  • Intracellular Signaling Peptides and Proteins
  • Muscle Proteins
  • Proteins
  • Tumor Suppressor Protein p53
  • Poly(ADP-ribose) Polymerases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases