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Effects of Low Ionic Strength and Calmodulin on the Decline in Maximal Calcium-Activated Force in Permeabilized Smooth Muscle

  • C. A. Crichton
  • G. L. Smith
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 311)

Summary

Maximal calcium-activated tension (Tmax) was measured from saponin-and alpha-toxin permemabilized strips of rat anococcygeus muscle stimulated repetitively. 50 mins after saponin treatment, Tmax had declined to 20% of the initial value. Calmodulin (1µM) only partially reduced this decline. Lowering the ionic strength of the bathing solution from 0.2M to 0.07M markedly reduced the rate of decline of tension. Addition of calmodulin to the bathing medium of low ionic strength prevented the decline of force still further; 50 mins after permeabilization, Tmax declined to 80% of the original level. Loss of endogenous calmodulin should be prevented by permeabilization with alpha-toxin from Staphylococcus aureus. Nevertheless, Tmax still declined to approximately 50% of the original value after 50mins. However, negligible force reduction was observed if the bathing solution had an ionic strength of 0.07M.

Keywords

Ionic Strength Bathing Solution Bathing Medium British Heart Foundation Skinned Muscle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. Itoh, T., Kanumura, Y. & Kuriyama, H. (1986) Inorganic phosphate regulates the contraction-relaxation cycle in skinned muscles of the rabbit mesenteric artery. Journal of Physiology 376, 231–252PubMedGoogle Scholar
  2. Kossman, T., Furst, D. & Small, J.V. (1987) Structural and biochemical analysis of skinned smooth muscle preparations. Journal of Muscle Research and Cell Motility 8, 135–144CrossRefGoogle Scholar
  3. Gardner, J.P., Stout, M.A. & Harris, S.R. (1989) Calmodulin loss in vascular smooth muscle following Triton X-100 or saponin skinning. Pflugers Archiv 414, 484–491PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1992

Authors and Affiliations

  • C. A. Crichton
    • 1
  • G. L. Smith
    • 1
  1. 1.Institute of PhysiologyUniversity of GlasgowGlasgowScotland

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