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Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine

The effect of the plant alkaloid aconitine on sodium channel kinetics, ionic selectivity, and blockage by protons and tetrodotoxin (TTX) has been studied in frog skeletal muscle. Treatment with 0.25 or 0.3 mM aconitine alters sodium channels so that the threshold of activation is shifted 40-50 mV in...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1982
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Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228644/
https://www.ncbi.nlm.nih.gov/pubmed/6294221
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description The effect of the plant alkaloid aconitine on sodium channel kinetics, ionic selectivity, and blockage by protons and tetrodotoxin (TTX) has been studied in frog skeletal muscle. Treatment with 0.25 or 0.3 mM aconitine alters sodium channels so that the threshold of activation is shifted 40-50 mV in the hyperpolarized direction. In contrast to previous results in frog nerve, inactivation is complete for depolarizations beyond about -60 mV. After aconitine treatment, the steady state level of inactivation is shifted approximately 20 mV in the hyperpolarizing direction. Concomitant with changes in channel kinetics, the relative permeability of the sodium channel to NH4,K, and Cs is increased. This altered selectivity is not accompanied by altered block by protons or TTX. The results suggest that sites other than those involved in channel block by protons and TTX are important in determining sodium channel selectivity.
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spelling pubmed-22286442008-04-23 Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine J Gen Physiol Articles The effect of the plant alkaloid aconitine on sodium channel kinetics, ionic selectivity, and blockage by protons and tetrodotoxin (TTX) has been studied in frog skeletal muscle. Treatment with 0.25 or 0.3 mM aconitine alters sodium channels so that the threshold of activation is shifted 40-50 mV in the hyperpolarized direction. In contrast to previous results in frog nerve, inactivation is complete for depolarizations beyond about -60 mV. After aconitine treatment, the steady state level of inactivation is shifted approximately 20 mV in the hyperpolarizing direction. Concomitant with changes in channel kinetics, the relative permeability of the sodium channel to NH4,K, and Cs is increased. This altered selectivity is not accompanied by altered block by protons or TTX. The results suggest that sites other than those involved in channel block by protons and TTX are important in determining sodium channel selectivity. The Rockefeller University Press 1982-11-01 /pmc/articles/PMC2228644/ /pubmed/6294221 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
Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
title Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
title_full Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
title_fullStr Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
title_full_unstemmed Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
title_short Modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
title_sort modified kinetics and selectivity of sodium channels in frog skeletal muscle fibers treated with aconitine
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228644/
https://www.ncbi.nlm.nih.gov/pubmed/6294221