Pflügers Archiv

, Volume 400, Issue 2, pp 160–165 | Cite as

The relationship between ATP hydrolysis and active force in compressed and swollen skinned muscle fibers of the rabbit

  • Brian Krasner
  • David Maughan
Heart, Circulation, Respiration and blood; Environmental and Exercise Physiology

Abstract

We investigated whether the inhibition of force generation observed in compressed muscle fibers is accompanied by a coupled reduction in hydrolytic activity. Isometric force and rates of ATP hydrolysis (ATPase) were measured as functions of the relative width of chemically skinned skeletal muscle fiber segments immersed in relaxing (pCa>8) and activating (pCa 4.9) salt solutions. Osmotic radial compression of the fiber segment was produced (with little or no affect on striation spacing) by adding Dextran T500 to the bathing media. ADP as a product of ATP hydrolysis in fibers undergoing 10–15 min contractions was measured using high pressure liquid chromatography. Compression of the (initially swollen) fiber segment with dextran produced a slight (4%) increase in average active force and then, with further compression, a sharp decrease (with maximum around in situ width). With compression, the average ATPase of the fiber decreased monotonically, and with extreme compression (with 0.22 g dextran per ml), ATPase fell to a fifth of its level determined in dextran-free solution while force was abolished. The time course of active force development was described by the sum of two exponential functions, the faster of which characterized the rate of rise. Fiber compression (0.14 g dextran per ml) reduced the rate of rise of force ten-fold compared to that in dextran-free solution. Hindrance of cross movement is proposed to account for the inhibition of active force generation and (coupled) ATPase in compressed fibers.

Key words

Skinned fiber Muscle force Actomyosin ATPase Osmotic compression 

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References

  1. April EW, Maughan DW (1982) Correlation between interfilament spacing and force generation in striated muscle. Biophys J 37 (2):129aGoogle Scholar
  2. Berman MR, Maughan DW (1982) Axial elastic modulus as a function of relative fiber width in relaxed skinned skeletal muscle fibers. Pflügers Arch 393:99–103Google Scholar
  3. Fabiato A, Fabiato F (1979) Calculator programs for computing the composition of the solutions containing multiple metals and ligands used for experiments in skinned muscle cells. J Physiol 75:463–505Google Scholar
  4. Godt RE, Lindley BD (1982) Influence of temperature upon contractile activation and isometric force production in mechanically skinned muscle fibers of the frog. J Gen Physiol 80:279–297Google Scholar
  5. Godt RE, Maughan DW (1981) Influence of osmotic compression on calcium activation and tension in skinned muscle fibers of the rabbit. Pflügers Arch 391:334–337Google Scholar
  6. Huxley AF, Simmons RM (1973) Mechanical transients and the origin of muscular force. Cold Spring Harb Symp Quant Biol 37:669–680Google Scholar
  7. Krasner B (1979) Nonparallel isometric tension response of rabbit soleus skinned muscle fibers to magnesium adenosine triphosphate and magnesium inosine triphosphate. J Gen Physiol 74:261–274Google Scholar
  8. Krasner B, Kushmerick M (1980) Dibucaine inhibits SR ATPase and increases sensitivity of “skinned” soleus muscle fibers to calcium. Fed Proc 39:2173Google Scholar
  9. Kushmerick MJ, Krasner B (1982) Force and ATPase rate in skinned skeletal muscle fibers. Fed Proc 14:2232–2237Google Scholar
  10. Levy RM, Umazume Y, Kushmerick MJ (1976) Ca2+ dependence of tension and ADP production in segments of chemically skinned muscle fibers. Biochim Biophys Acta 430:352–365Google Scholar
  11. Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193: 265–275Google Scholar
  12. Maughan DW (1982) Use of functionally-skinned tissue in studying altered contractility in hypertrophied myocardium. In: Alpert NR (ed) Perspectives in cardiovascular research, vol 7. Myocardial hypertrophy and failure. Raven Press, New YorkGoogle Scholar
  13. Maughan DW, Godt RE (1981) Inhibition of force production in compressed skinned muscle fibers of the frog. Pflügers Arch 390:161–163Google Scholar
  14. Rome E (1972) Relaxation of glycerinated muscle: Low-angle X-ray diffraction studies. J Mol Biol 65:331–345Google Scholar
  15. Schoenberg M (1980) Geometrical factors influencing muscle force development. I. The effect of filament spacing upon axial forces. Biophys J 30:51–68Google Scholar
  16. Stephenson EW (1981) Activation of fast skeletal muscle: Contributions of studies on skinned fibers. Am J Physiol 240 (Cell Physiol. 9):C1–19Google Scholar
  17. Vink H (1971) Precision measurements of osmotic pressure in concentrated polymer solutions. Eur Polymer J 7:1411–1419Google Scholar

Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Brian Krasner
    • 1
  • David Maughan
    • 2
  1. 1.Department of PhysiologyHarvard Medical SchoolBoston
  2. 2.Department of Physiology and BiophysicsUniversity of VermontBurlingtonUSA

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