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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...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1977
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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. |
format | Text |
id | pubmed-2228511 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1977 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
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 |