Tension and P liberation were determined at the same time in glycerol-extracted muscle fibers suspended in ATP solutions. In the relaxed state, produced by ATP in rather fresh preparations, P liberation was low, but somewhat higher than in normal resting muscle. On addition of small amounts of CaCl2 the fibers gave a strong contraction during which P liberation was on the average about 5 times higher than in the relaxed condition. In aged muscle fibers ATP always produced a strong contraction associated with a high ATPase activity which was not influenced by Ca. The P liberation during a sustained contraction was much smaller in extracted fibers than in normal muscle, but the former maintained tension much more economically than the latter, resembling smooth muscle in this respect. Also the removal of Mg caused a contraction associated with high ATPase activity. Mg, therefore, is inhibitory in relaxed fibers. In fibers activated by Ca or by aging, however, it caused enhancement. The effects of ions on ATPase activity of relaxed fibers are similar to those on myosin and dissociated actomyosin, whereas activated fibers resemble actomyosin at low salt concentration.
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20 September 1953
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September 20 1953
THE CONTROL OF ENERGY RELEASE IN EXTRACTED MUSCLE FIBERS
Emil Bozler,
Emil Bozler
From the Department of Physiology, The Ohio State University, Columbus
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J. T. Prince
J. T. Prince
From the Department of Physiology, The Ohio State University, Columbus
Search for other works by this author on:
Emil Bozler
From the Department of Physiology, The Ohio State University, Columbus
J. T. Prince
From the Department of Physiology, The Ohio State University, Columbus
Received:
February 18 1953
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright, 1953, by The Rockefeller Institute for Medical Research
1953
J Gen Physiol (1953) 37 (1): 53–61.
Article history
Received:
February 18 1953
Citation
Emil Bozler, J. T. Prince; THE CONTROL OF ENERGY RELEASE IN EXTRACTED MUSCLE FIBERS . J Gen Physiol 20 September 1953; 37 (1): 53–61. doi: https://doi.org/10.1085/jgp.37.1.53
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