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Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle

The effect of shortening on contractile activity was studied in experiments in which shortening during the rising phase of an isotonic contraction was suddenly stopped. At the same muscle length and the same time after stimulation the rise in tension was much faster, if preceded by shortening, than...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1977
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228511/
https://www.ncbi.nlm.nih.gov/pubmed/591919
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collection PubMed
description The effect of shortening on contractile activity was studied in experiments in which shortening during the rising phase of an isotonic contraction was suddenly stopped. At the same muscle length and the same time after stimulation the rise in tension was much faster, if preceded by shortening, than during an isometric contraction, demonstrating an increase in contractile activity. In this experiment the rate of tension rise determined in various phases of contraction was proportional to the rate of isotonic shortening at the same time after stimulation. Therefore, the time course of the isotonic rising phase could be derived from the tension rise after shortening. The rate of isotonic shortening was found to be unrelated to the tension generated at various lengths and to correspond closely to the activation process induced by shortening. The length response explains differences between isotonic and isometric contractions with regard to energy release (Fenn effect) and time relations. These results extend previous work which showed that shortening during later phases of a twitch prolongs, while lengthening abbreviates contraction. Thus the length responses, which have been called shortening activation and lengthening deactivation, control activity throughout an isotonic twitch.
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spelling pubmed-22285112008-04-23 Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle J Gen Physiol Articles The effect of shortening on contractile activity was studied in experiments in which shortening during the rising phase of an isotonic contraction was suddenly stopped. At the same muscle length and the same time after stimulation the rise in tension was much faster, if preceded by shortening, than during an isometric contraction, demonstrating an increase in contractile activity. In this experiment the rate of tension rise determined in various phases of contraction was proportional to the rate of isotonic shortening at the same time after stimulation. Therefore, the time course of the isotonic rising phase could be derived from the tension rise after shortening. The rate of isotonic shortening was found to be unrelated to the tension generated at various lengths and to correspond closely to the activation process induced by shortening. The length response explains differences between isotonic and isometric contractions with regard to energy release (Fenn effect) and time relations. These results extend previous work which showed that shortening during later phases of a twitch prolongs, while lengthening abbreviates contraction. Thus the length responses, which have been called shortening activation and lengthening deactivation, control activity throughout an isotonic twitch. The Rockefeller University Press 1977-12-01 /pmc/articles/PMC2228511/ /pubmed/591919 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
title Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
title_full Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
title_fullStr Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
title_full_unstemmed Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
title_short Mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
title_sort mechanical control of the rising phase of contraction of frog skeletal and cardiac muscle
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228511/
https://www.ncbi.nlm.nih.gov/pubmed/591919