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Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process
Evidence is presented showing that the Cl- uptake process in the squid giant axon is tightly coupled not only to Na+ uptake but also to K+ uptake. Thus, removal of external K+ causes both Cl- and Na+ influxes to be reduced, particularly when [Cl-]i is low, that is, under conditions previously shown...
Formato: | Texto |
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Lenguaje: | English |
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The Rockefeller University Press
1983
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2215554/ https://www.ncbi.nlm.nih.gov/pubmed/6875510 |
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collection | PubMed |
description | Evidence is presented showing that the Cl- uptake process in the squid giant axon is tightly coupled not only to Na+ uptake but also to K+ uptake. Thus, removal of external K+ causes both Cl- and Na+ influxes to be reduced, particularly when [Cl-]i is low, that is, under conditions previously shown to be optimal for Cl-/Na+-coupled influx. In addition, there exists a ouabain-insensitive K+ influx, which depends on the presence of external Cl- and Na+, is inversely proportional to [Cl-]i, and is blocked by furosemide/bumetanide. Finally, this ouabain-insensitive K+ influx appears to require the presence of cellular ATP. The stoichiometry of the coupled transport process was measured using a double-labeling technique combining in the same axon either 36Cl and 42K or 22Na and 42K. The stoichiometry of the flux changes occurring in response either to varying [Cl-]i between 150 and 0 mM or to treatment with 0.3 mM furosemide is, in both cases, approximately 3:2:1 (Cl-/Na+/K+). Although these fluxes require ATP, they are not inhibited by 3 mM vanadate. In addition, treatment with DIDS has no effect on the fluxes. |
format | Text |
id | pubmed-2215554 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1983 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22155542008-04-23 Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process J Gen Physiol Articles Evidence is presented showing that the Cl- uptake process in the squid giant axon is tightly coupled not only to Na+ uptake but also to K+ uptake. Thus, removal of external K+ causes both Cl- and Na+ influxes to be reduced, particularly when [Cl-]i is low, that is, under conditions previously shown to be optimal for Cl-/Na+-coupled influx. In addition, there exists a ouabain-insensitive K+ influx, which depends on the presence of external Cl- and Na+, is inversely proportional to [Cl-]i, and is blocked by furosemide/bumetanide. Finally, this ouabain-insensitive K+ influx appears to require the presence of cellular ATP. The stoichiometry of the coupled transport process was measured using a double-labeling technique combining in the same axon either 36Cl and 42K or 22Na and 42K. The stoichiometry of the flux changes occurring in response either to varying [Cl-]i between 150 and 0 mM or to treatment with 0.3 mM furosemide is, in both cases, approximately 3:2:1 (Cl-/Na+/K+). Although these fluxes require ATP, they are not inhibited by 3 mM vanadate. In addition, treatment with DIDS has no effect on the fluxes. The Rockefeller University Press 1983-06-01 /pmc/articles/PMC2215554/ /pubmed/6875510 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 Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process |
title | Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process |
title_full | Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process |
title_fullStr | Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process |
title_full_unstemmed | Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process |
title_short | Cation-coupled chloride influx in squid axon. Role of potassium and stoichiometry of the transport process |
title_sort | cation-coupled chloride influx in squid axon. role of potassium and stoichiometry of the transport process |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2215554/ https://www.ncbi.nlm.nih.gov/pubmed/6875510 |