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The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations
After a 20 min initial washout, the rate of loss of radioactively labeled sodium ions from sodium-enriched muscle cells is sensitive to the external sodium and potassium ion concentrations. In the absence of external potassium ions, the presence of external sodium ions increases the sodium efflux. I...
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1971
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203079/ https://www.ncbi.nlm.nih.gov/pubmed/5543416 |
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author | Sjodin, R. A. |
author_facet | Sjodin, R. A. |
author_sort | Sjodin, R. A. |
collection | PubMed |
description | After a 20 min initial washout, the rate of loss of radioactively labeled sodium ions from sodium-enriched muscle cells is sensitive to the external sodium and potassium ion concentrations. In the absence of external potassium ions, the presence of external sodium ions increases the sodium efflux. In the presence of external potassium ions, the presence of external sodium ions decreases the sodium efflux. In the absence of external potassium ions about one-third of the Na(+) efflux that depends upon the external sodium ion concentration can be abolished by 10(-5) M glycoside. The glycoside-insensitive but external sodium-dependent Na(+) efflux is uninfluenced by external potassium ions. In the absence of both external sodium and potassium ions the sodium efflux is relatively insensitive to the presence of 10(-5) M glycoside. The maximal external sodium-dependent sodium efflux in the absence of external potassium ions is about 20% of the magnitude of the maximal potassium-dependent sodium efflux. The magnitude of the glycoside-sensitive sodium efflux in K-free Ringer solution is less than 10% of that observed when sodium efflux is maximally activated by potassium ions. The inhibition of the potassium-activated sodium efflux by external sodium ions is of the competitive type. Reducing the external sodium ion concentration displaces the plots of sodium extrusion rate vs. [K](o) to the left and upwards. |
format | Text |
id | pubmed-2203079 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1971 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22030792008-04-23 The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations Sjodin, R. A. J Gen Physiol Article After a 20 min initial washout, the rate of loss of radioactively labeled sodium ions from sodium-enriched muscle cells is sensitive to the external sodium and potassium ion concentrations. In the absence of external potassium ions, the presence of external sodium ions increases the sodium efflux. In the presence of external potassium ions, the presence of external sodium ions decreases the sodium efflux. In the absence of external potassium ions about one-third of the Na(+) efflux that depends upon the external sodium ion concentration can be abolished by 10(-5) M glycoside. The glycoside-insensitive but external sodium-dependent Na(+) efflux is uninfluenced by external potassium ions. In the absence of both external sodium and potassium ions the sodium efflux is relatively insensitive to the presence of 10(-5) M glycoside. The maximal external sodium-dependent sodium efflux in the absence of external potassium ions is about 20% of the magnitude of the maximal potassium-dependent sodium efflux. The magnitude of the glycoside-sensitive sodium efflux in K-free Ringer solution is less than 10% of that observed when sodium efflux is maximally activated by potassium ions. The inhibition of the potassium-activated sodium efflux by external sodium ions is of the competitive type. Reducing the external sodium ion concentration displaces the plots of sodium extrusion rate vs. [K](o) to the left and upwards. The Rockefeller University Press 1971-02-01 /pmc/articles/PMC2203079/ /pubmed/5543416 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 Sjodin, R. A. The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations |
title | The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations |
title_full | The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations |
title_fullStr | The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations |
title_full_unstemmed | The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations |
title_short | The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations |
title_sort | kinetics of sodium extrusion in striated muscle as functions of the external sodium and potassium ion concentrations |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203079/ https://www.ncbi.nlm.nih.gov/pubmed/5543416 |
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