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Pharmacological Modifications of the Sodium Channels of Frog Nerve

Voltage clamp measurements on myelinated nerve fibers show that tetrodotoxin, saxitoxin, and DDT specifically affect the sodium channels of the membrane. Tetrodotoxin and saxitoxin render the sodium channels impermeable to Na ions and to Li ions and probably prevent the opening of individual sodium...

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Detalles Bibliográficos
Autor principal: Hille, Bertil
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1968
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2201123/
https://www.ncbi.nlm.nih.gov/pubmed/5641635
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author Hille, Bertil
author_facet Hille, Bertil
author_sort Hille, Bertil
collection PubMed
description Voltage clamp measurements on myelinated nerve fibers show that tetrodotoxin, saxitoxin, and DDT specifically affect the sodium channels of the membrane. Tetrodotoxin and saxitoxin render the sodium channels impermeable to Na ions and to Li ions and probably prevent the opening of individual sodium channels when one toxin molecule binds to a channel. The apparent dissociation constant of the inhibitory complex is about 1 nM for the cationic forms of both toxins. The zwitter ionic forms are much less potent. On the other hand, DDT causes a fraction of the sodium channels that open during a depolarization to remain open for a longer time than is normal. The effect cannot be described as a specific change in sodium inactivation or as a specific change in sodium activation, for both processes continue to govern the opening of the sodium channels and neither process is able to close the channels. The effects of DDT are very similar to those of veratrine.
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spelling pubmed-22011232008-04-23 Pharmacological Modifications of the Sodium Channels of Frog Nerve Hille, Bertil J Gen Physiol Article Voltage clamp measurements on myelinated nerve fibers show that tetrodotoxin, saxitoxin, and DDT specifically affect the sodium channels of the membrane. Tetrodotoxin and saxitoxin render the sodium channels impermeable to Na ions and to Li ions and probably prevent the opening of individual sodium channels when one toxin molecule binds to a channel. The apparent dissociation constant of the inhibitory complex is about 1 nM for the cationic forms of both toxins. The zwitter ionic forms are much less potent. On the other hand, DDT causes a fraction of the sodium channels that open during a depolarization to remain open for a longer time than is normal. The effect cannot be described as a specific change in sodium inactivation or as a specific change in sodium activation, for both processes continue to govern the opening of the sodium channels and neither process is able to close the channels. The effects of DDT are very similar to those of veratrine. The Rockefeller University Press 1968-02-01 /pmc/articles/PMC2201123/ /pubmed/5641635 Text en Copyright © 1968 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
Hille, Bertil
Pharmacological Modifications of the Sodium Channels of Frog Nerve
title Pharmacological Modifications of the Sodium Channels of Frog Nerve
title_full Pharmacological Modifications of the Sodium Channels of Frog Nerve
title_fullStr Pharmacological Modifications of the Sodium Channels of Frog Nerve
title_full_unstemmed Pharmacological Modifications of the Sodium Channels of Frog Nerve
title_short Pharmacological Modifications of the Sodium Channels of Frog Nerve
title_sort pharmacological modifications of the sodium channels of frog nerve
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2201123/
https://www.ncbi.nlm.nih.gov/pubmed/5641635
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