Regulation of force in skinned, single cells of ferret aortic smooth muscle

Frank V. Brozovich, Michael P. Walsh, Kathleen G. Morgan

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

An isolation technique was developed for single cells from the ferret aorta, which resulted in the isolation of long (87±27 μm; x±SD, n=62), relaxed, pharmacologically active smooth muscle cells. These cells were attached to microtools, one of which was connected to a force transducer. Force in maximally phenylephrine-stimulated contractions of the intact cells averaged 2.3 ±1.4 μN (n=17). After cell skinning with saponin, the threshold for force development was 0.05 μM [Ca2+], and force reached a maximum of 4.4±1.6 μN (n = 36) at 0.5 μM [Ca2+]. Plots of relative steady-state force vs pCa (-log10[Ca2+]) were fit to the Hill equation, which yielded a pCa at half-maximal force of 6.87 ± 0.30 and a Hill coefficient of 2.3±1.4 (n = 29). When 2.5 μM calmodulin was added to the solutions, the calcium sensitivity of force was significantly increased (P<0.05) without changing the maximal force (P>0.05). In a solution of pCa 7, the skinned cells developed 2.5±0.5 μN (n = 5) of force when stimulated with a phorbol ester. The addition of a specific inhibitor (17 kDa) of protein kinase C to the calcium buffers depressed (P<0.05) the maximally Ca2+ -activated force without a change in the calcium sensitivity of force (P>0.05). These data strongly suggest that in vascular smooth muscle, protein kinase C may be involved in a physiological, regulatory system for force.

Original languageEnglish (US)
Pages (from-to)742-749
Number of pages8
JournalPflügers Archiv European Journal of Physiology
Volume416
Issue number6
DOIs
StatePublished - Aug 1990

Keywords

  • Excitation/contraction coupling
  • Protein kinase C
  • Vascular smooth muscle

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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