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Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp
Membrane currents associated with voltage clamp of the giant muscle fibers of a barnacle, Balanus nubilus, were analyzed in terms of currents of the Ca and K channels. Although the activation of the K channel occurs more slowly than that of the Ca channel, both currents show a significant temporal o...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1974
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203570/ https://www.ncbi.nlm.nih.gov/pubmed/4824996 |
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author | Hagiwara, Susumu Fukuda, Jun Eaton, Douglas C. |
author_facet | Hagiwara, Susumu Fukuda, Jun Eaton, Douglas C. |
author_sort | Hagiwara, Susumu |
collection | PubMed |
description | Membrane currents associated with voltage clamp of the giant muscle fibers of a barnacle, Balanus nubilus, were analyzed in terms of currents of the Ca and K channels. Although the activation of the K channel occurs more slowly than that of the Ca channel, both currents show a significant temporal overlap. The currents carried by Ca(++), Sr(++), or Ba(++) through the Ca channel were compared under the conditions at which this overlap was the least. When only one divalent cation is present in the solution, Ba(++) carries more current than Ca(++) or Sr(++) and the sequence of the current is Ba > Sr ≈ Ca. When the external solution contains a relatively high concentration of Co(++), which is a blocking agent for the Ca channel, inversion of the sequence occurs, to Ca > Sr > Ba. This is due to the fact that the blocking effect differs depending on which ion carries current through the Ca channel. The Ba current is most sensitive and the Ca current is least affected. Ba suppresses the current of the K channel, independently of its current-carrying function through the Ca channel. |
format | Text |
id | pubmed-2203570 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1974 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22035702008-04-23 Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp Hagiwara, Susumu Fukuda, Jun Eaton, Douglas C. J Gen Physiol Article Membrane currents associated with voltage clamp of the giant muscle fibers of a barnacle, Balanus nubilus, were analyzed in terms of currents of the Ca and K channels. Although the activation of the K channel occurs more slowly than that of the Ca channel, both currents show a significant temporal overlap. The currents carried by Ca(++), Sr(++), or Ba(++) through the Ca channel were compared under the conditions at which this overlap was the least. When only one divalent cation is present in the solution, Ba(++) carries more current than Ca(++) or Sr(++) and the sequence of the current is Ba > Sr ≈ Ca. When the external solution contains a relatively high concentration of Co(++), which is a blocking agent for the Ca channel, inversion of the sequence occurs, to Ca > Sr > Ba. This is due to the fact that the blocking effect differs depending on which ion carries current through the Ca channel. The Ba current is most sensitive and the Ca current is least affected. Ba suppresses the current of the K channel, independently of its current-carrying function through the Ca channel. The Rockefeller University Press 1974-05-01 /pmc/articles/PMC2203570/ /pubmed/4824996 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 | Article Hagiwara, Susumu Fukuda, Jun Eaton, Douglas C. Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp |
title | Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp |
title_full | Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp |
title_fullStr | Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp |
title_full_unstemmed | Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp |
title_short | Membrane Currents Carried by Ca, Sr, and Ba in Barnacle Muscle Fiber During Voltage Clamp |
title_sort | membrane currents carried by ca, sr, and ba in barnacle muscle fiber during voltage clamp |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203570/ https://www.ncbi.nlm.nih.gov/pubmed/4824996 |
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