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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...

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Detalles Bibliográficos
Autores principales: Hagiwara, Susumu, Fukuda, Jun, Eaton, Douglas C.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1974
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.
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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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