Force maintenance in smooth muscle: Analysis using sinusoidal perturbations

Albert Y. Rhee, Frank V. Brozovich

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

The "latch state" or force maintenance may be due to the emergence of a distinct set of dephosphorylated, slowly cycling "latch" cross-bridges, slowing of the overall cross-bridge cycling rate, or a non-cross-bridge contribution. This was investigated by sinusoidally oscillating strips of intact rabbit portal vein or aorta. Tissue strips were activated with KCl depolarization, resulting in a sustained increase of MLC20 phosphorylation or 10μM phenylephrine, resulting in a transient increase in MLC20 phosphorylation. Stiffness was calculated from the force response to a small, sine-wave oscillation in muscle length (1-100Hz). The results produced a 3-dimensional plot of stiffness versus the frequency of oscillation (Hz) versus time (s), or stiffness distribution profile. During KCl depolarization, the stiffness distribution profile displayed a shift toward lower frequencies, suggesting a general slowing in the overall cross-bridge cycling rate during force maintenance. On the other hand, phenylephrine stimulation did not display a significant change in the stiffness distribution profile, suggesting that the overall cross-bridge cycling rate did not significantly change during force maintenance.

Original languageEnglish (US)
Pages (from-to)25-38
Number of pages14
JournalArchives of Biochemistry and Biophysics
Volume410
Issue number1
DOIs
StatePublished - Feb 1 2003

Keywords

  • Force maintenance
  • KCl
  • MLC
  • Phenylephrine
  • Smooth muscle
  • Stiffness

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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