Stimulus-specific changes in mechanical properties of vascular smooth muscle

F. V. Brozovich, K. G. Morgan

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

To determine whether the mechanical properties of vascular smooth muscle are stimulus specific, force, stiffness, and the unloaded shortening velocity (V(max)) were measured during contractions of aortic smooth muscle strips stimulated with phenylephrine or KCl. After activation, muscle force and stiffness rose to a steady-state plateau where they were maintained. In phenylephrine contractions, V(max) peaked during force development and then fell to a lower steady-state level during force maintenance, whereas in the KCl contractions, V(max) did not decline during sustained contractions. Stimulation with KCl, compared with phenylephrine, produced lower steady-state forces. One possible interpretation is that the muscle formed latch cross-bridges during phenylephrine contractions, but during KCl depolarizations. The slope of the plot of relative muscle force vs. stiffness for phenylephrine contractions, compared with KCl depolarizations, was reduced. This may imply that the relative force per attached latch cross-bridge could be reduced.

Original languageEnglish (US)
Pages (from-to)26/5
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume257
Issue number5
StatePublished - Jan 1 1989

Keywords

  • force maintenance
  • latch
  • mechanics
  • smooth muscle tone

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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