Inhibition of the p38 MAP kinase pathway destabilizes smooth muscle length during physiological loading

Oren J. Lakser, Robert P. Lindeman, Jeffrey J. Fredberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


We tested the hypothesis that mechanical plasticity of airway smooth muscle may be mediated in part by the p38 mitogen-activated protein (MAP) kinase pathway. Bovine tracheal smooth muscle (TSM) strips were mounted in a muscle bath and set to their optimal length, where the active force was maximal (Fo). Each strip was then contracted isotonically (at 0.32 Fo) with ACh (maintained at 10-4 M) and allowed to shorten for 180 min, by which time shortening was completed and the static equilibrium length was established. To simulate the action of breathing, we then superimposed on this steady distending force a sinusoidal force fluctuation with zero mean, at a frequency of 0.2 Hz, and measured incremental changes in muscle length. We found that TSM strips incubated in 10 μM SB-203580-HC1, an inhibitor of the p38 MAP kinase pathway, demonstrated a greater degree of fluctuation-driven lengthening than did control strips, and upon removal of the force fluctuations they remained at a greater length. We also found that the force fluctuations themselves activated the p38 MAP kinase pathway. These findings are consistent with the hypothesis that inhibition of the p38 MAP kinase pathway destabilizes muscle length during physiological loading.

Original languageEnglish (US)
Pages (from-to)L1117-L1121
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number5 26-5
StatePublished - 2002


  • Contraction
  • Mitogen-activated protein
  • Perturbed myosin binding
  • Plasticity

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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