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Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique
A method similar to the sucrose-gap technique introduced be Stäpfli is described for measuring membrane potential and current in singly lobster giant axons (diameter about 100 micra). The isotonic sucrose solution used to perfuse the gaps raises the external leakage resistance so that the recorded p...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1962
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2195233/ https://www.ncbi.nlm.nih.gov/pubmed/14452759 |
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author | Julian, Fred J. Moore, John W. Goldman, David E. |
author_facet | Julian, Fred J. Moore, John W. Goldman, David E. |
author_sort | Julian, Fred J. |
collection | PubMed |
description | A method similar to the sucrose-gap technique introduced be Stäpfli is described for measuring membrane potential and current in singly lobster giant axons (diameter about 100 micra). The isotonic sucrose solution used to perfuse the gaps raises the external leakage resistance so that the recorded potential is only about 5 per cent less than the actual membrane potential. However, the resting potential of an axon in the sucrose-gap arrangement is increased 20 to 60 mv over that recorded by a conventional micropipette electrode when the entire axon is bathed in sea water. A complete explanation for this effect has not been discovered. The relation between resting potential and external potassium and sodium ion concentrations shows that potassium carries most of the current in a depolarized axon in the sucrose-gap arrangement, but that near the resting potential other ions make significant contributions. Lowering the external chloride concentration decreases the resting potential. Varying the concentration of the sucrose solution has little effect. A study of the impedance changes associated with the action potential shows that the membrane resistance decreases to a minimum at the peak of the spike and returns to near its initial value before repolarization is complete (a normal lobster giant axon action potential does not have an undershoot). Action potentials recorded simultaneously by the sucrose-gap technique and by micropipette electrodes are practically superposable. |
format | Text |
id | pubmed-2195233 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1962 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21952332008-04-23 Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique Julian, Fred J. Moore, John W. Goldman, David E. J Gen Physiol Article A method similar to the sucrose-gap technique introduced be Stäpfli is described for measuring membrane potential and current in singly lobster giant axons (diameter about 100 micra). The isotonic sucrose solution used to perfuse the gaps raises the external leakage resistance so that the recorded potential is only about 5 per cent less than the actual membrane potential. However, the resting potential of an axon in the sucrose-gap arrangement is increased 20 to 60 mv over that recorded by a conventional micropipette electrode when the entire axon is bathed in sea water. A complete explanation for this effect has not been discovered. The relation between resting potential and external potassium and sodium ion concentrations shows that potassium carries most of the current in a depolarized axon in the sucrose-gap arrangement, but that near the resting potential other ions make significant contributions. Lowering the external chloride concentration decreases the resting potential. Varying the concentration of the sucrose solution has little effect. A study of the impedance changes associated with the action potential shows that the membrane resistance decreases to a minimum at the peak of the spike and returns to near its initial value before repolarization is complete (a normal lobster giant axon action potential does not have an undershoot). Action potentials recorded simultaneously by the sucrose-gap technique and by micropipette electrodes are practically superposable. The Rockefeller University Press 1962-07-01 /pmc/articles/PMC2195233/ /pubmed/14452759 Text en Copyright © Copyright, 1962, by The Rockefeller Institute 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 Julian, Fred J. Moore, John W. Goldman, David E. Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique |
title | Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique |
title_full | Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique |
title_fullStr | Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique |
title_full_unstemmed | Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique |
title_short | Membrane Potentials of the Lobster Giant Axon Obtained by Use of the Sucrose-Gap Technique |
title_sort | membrane potentials of the lobster giant axon obtained by use of the sucrose-gap technique |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2195233/ https://www.ncbi.nlm.nih.gov/pubmed/14452759 |
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