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High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle

Contractures develop in sheep atrial trabeculae if Tyrode's solution is rapidly replaced by a solution containing elevated potassium, reduced sodium, or both. Two phases of the contracture can be identified on the basis of differences in physiological behavior: a rapid and transient phase that...

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Detalles Bibliográficos
Autores principales: Gibbons, W. R., Fozzard, H. A.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1971
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226041/
https://www.ncbi.nlm.nih.gov/pubmed/5122370
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author Gibbons, W. R.
Fozzard, H. A.
author_facet Gibbons, W. R.
Fozzard, H. A.
author_sort Gibbons, W. R.
collection PubMed
description Contractures develop in sheep atrial trabeculae if Tyrode's solution is rapidly replaced by a solution containing elevated potassium, reduced sodium, or both. Two phases of the contracture can be identified on the basis of differences in physiological behavior: a rapid and transient phase that predominates during the first few seconds of the contracture, and a slowly developed phase that is responsible for the steady level of tension reached later in the contracture. The transient phase is particularly prominent if the muscle is stimulated rapidly before the contracture, and reduced or absent if the muscle is not stimulated or if calcium is not present before the contracture. Recovery of the transient phase after a contracture parallels the recovery of twitches. This transient phase appears to reflect the depolarization-induced release of activator (calcium) from an internal store, possibly the same store that is involved in the normal contraction. The slowly developed tension is dependent on the contracture solution used, and is decreased if the calcium concentration is reduced or if the sodium concentration is increased. It does not depend on conditions before the contracture and does not require time to recover. This phase of the contracture may be due to entry of calcium from the extracellular solution.
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spelling pubmed-22260412008-04-23 High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle Gibbons, W. R. Fozzard, H. A. J Gen Physiol Article Contractures develop in sheep atrial trabeculae if Tyrode's solution is rapidly replaced by a solution containing elevated potassium, reduced sodium, or both. Two phases of the contracture can be identified on the basis of differences in physiological behavior: a rapid and transient phase that predominates during the first few seconds of the contracture, and a slowly developed phase that is responsible for the steady level of tension reached later in the contracture. The transient phase is particularly prominent if the muscle is stimulated rapidly before the contracture, and reduced or absent if the muscle is not stimulated or if calcium is not present before the contracture. Recovery of the transient phase after a contracture parallels the recovery of twitches. This transient phase appears to reflect the depolarization-induced release of activator (calcium) from an internal store, possibly the same store that is involved in the normal contraction. The slowly developed tension is dependent on the contracture solution used, and is decreased if the calcium concentration is reduced or if the sodium concentration is increased. It does not depend on conditions before the contracture and does not require time to recover. This phase of the contracture may be due to entry of calcium from the extracellular solution. The Rockefeller University Press 1971-11-01 /pmc/articles/PMC2226041/ /pubmed/5122370 Text en Copyright © 1971 by The Rockefeller University Press 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 Article
Gibbons, W. R.
Fozzard, H. A.
High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle
title High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle
title_full High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle
title_fullStr High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle
title_full_unstemmed High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle
title_short High Potassium and Low Sodium Contractures in Sheep Cardiac Muscle
title_sort high potassium and low sodium contractures in sheep cardiac muscle
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226041/
https://www.ncbi.nlm.nih.gov/pubmed/5122370
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