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On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri)
Sodium uptake by rainbow trout gills has been investigated with a small-volume system enabling rapid, successive flux measurements in different solutions. Sodium influx obeys a Michaelis-Menten type relation, with a K(m) of 0.46 mM, and uptake proceeds unimpaired in the absence of penetrating counte...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1970
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2225960/ https://www.ncbi.nlm.nih.gov/pubmed/5529209 |
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author | Kerstetter, Theodore H. Kirschner, Leonard B. Rafuse, Donald D. |
author_facet | Kerstetter, Theodore H. Kirschner, Leonard B. Rafuse, Donald D. |
author_sort | Kerstetter, Theodore H. |
collection | PubMed |
description | Sodium uptake by rainbow trout gills has been investigated with a small-volume system enabling rapid, successive flux measurements in different solutions. Sodium influx obeys a Michaelis-Menten type relation, with a K(m) of 0.46 mM, and uptake proceeds unimpaired in the absence of penetrating counter-ions. This suggests a coupled cation exchange. Ammonia output is about the same as the Na(+) influx when external [Na(+)] is 1 mM, but at higher or lower Na(+) influxes, the correlation does not hold. A progressive downward shift in the pH of the irrigating medium as Na(+) influx increases indicates that the exchanging cation is hydrogen. In support of this, acetazolamide, which inhibits Na(+) uptake, also prevents the downward pH shift. The potential across the gill is about 10 mv, body fluids positive, in NaCl solutions up to 10 mM, and is little affected by changes in Na(+) concentration below that. Finally, evidence for locating the rate-limiting step at the outer membrane of the epithelium is presented. |
format | Text |
id | pubmed-2225960 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1970 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22259602008-04-23 On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) Kerstetter, Theodore H. Kirschner, Leonard B. Rafuse, Donald D. J Gen Physiol Article Sodium uptake by rainbow trout gills has been investigated with a small-volume system enabling rapid, successive flux measurements in different solutions. Sodium influx obeys a Michaelis-Menten type relation, with a K(m) of 0.46 mM, and uptake proceeds unimpaired in the absence of penetrating counter-ions. This suggests a coupled cation exchange. Ammonia output is about the same as the Na(+) influx when external [Na(+)] is 1 mM, but at higher or lower Na(+) influxes, the correlation does not hold. A progressive downward shift in the pH of the irrigating medium as Na(+) influx increases indicates that the exchanging cation is hydrogen. In support of this, acetazolamide, which inhibits Na(+) uptake, also prevents the downward pH shift. The potential across the gill is about 10 mv, body fluids positive, in NaCl solutions up to 10 mM, and is little affected by changes in Na(+) concentration below that. Finally, evidence for locating the rate-limiting step at the outer membrane of the epithelium is presented. The Rockefeller University Press 1970-09-01 /pmc/articles/PMC2225960/ /pubmed/5529209 Text en Copyright © 1970 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 Kerstetter, Theodore H. Kirschner, Leonard B. Rafuse, Donald D. On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) |
title | On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) |
title_full | On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) |
title_fullStr | On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) |
title_full_unstemmed | On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) |
title_short | On the Mechanisms of Sodium Ion Transport by the Irrigated Gills of Rainbow Trout (Salmo gairdneri) |
title_sort | on the mechanisms of sodium ion transport by the irrigated gills of rainbow trout (salmo gairdneri) |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2225960/ https://www.ncbi.nlm.nih.gov/pubmed/5529209 |
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