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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...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1983
Materias:
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.
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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