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THE DIRECT CURRENT RESISTANCE OF NITELLA

The electrical resistance of Nitella cells to direct current is determined in a Wheatstone bridge, using a vacuum-tube detector, and string galvanometer. Very small currents are passed through the cells, to avoid stimulation. The galvanometer record shows typical transient effects in the living cell...

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Autor principal: Blinks, L. R.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1930
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2141060/
https://www.ncbi.nlm.nih.gov/pubmed/19872542
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author Blinks, L. R.
author_facet Blinks, L. R.
author_sort Blinks, L. R.
collection PubMed
description The electrical resistance of Nitella cells to direct current is determined in a Wheatstone bridge, using a vacuum-tube detector, and string galvanometer. Very small currents are passed through the cells, to avoid stimulation. The galvanometer record shows typical transient effects in the living cells at opening and closing of the circuit, due to the development of back E.M.F. With 1 cm. contacts of tap water, and 1 cm. between contacts the resistances of living cells are usually between 1,000,000 and 2,000,000 ohms. They go as high as 3,500,000 ohms when the cells are in the best condition. The resistance falls to about 50,000 ohms immediately after killing. Leakage around the cell is small because the wall is imbibed with tap water. By measuring the resistance of the isolated wall (air-filled), and by varying the areas of contact with intact cells, the effective protoplasmic resistance is calculated. This varies from 100,000 to 700,000 ohms per square centimeter of surface, with a typical value of about 250,000 ohms per square centimeter. This high resistance represents a low permeability for most ions, since the values are nearly as high with contacts of 0.01 M NaCl, CaCl(2), LiCl, NH(4)Cl, and MgSO(4). The resistances are greatly reduced however by solutions of KCl, which is correlated with a high mobility of the K(+) ion in the protoplasm. Electrical stimulation causes a marked reduction of resistance, which may be due to exomosis of KCl.
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spelling pubmed-21410602008-04-23 THE DIRECT CURRENT RESISTANCE OF NITELLA Blinks, L. R. J Gen Physiol Article The electrical resistance of Nitella cells to direct current is determined in a Wheatstone bridge, using a vacuum-tube detector, and string galvanometer. Very small currents are passed through the cells, to avoid stimulation. The galvanometer record shows typical transient effects in the living cells at opening and closing of the circuit, due to the development of back E.M.F. With 1 cm. contacts of tap water, and 1 cm. between contacts the resistances of living cells are usually between 1,000,000 and 2,000,000 ohms. They go as high as 3,500,000 ohms when the cells are in the best condition. The resistance falls to about 50,000 ohms immediately after killing. Leakage around the cell is small because the wall is imbibed with tap water. By measuring the resistance of the isolated wall (air-filled), and by varying the areas of contact with intact cells, the effective protoplasmic resistance is calculated. This varies from 100,000 to 700,000 ohms per square centimeter of surface, with a typical value of about 250,000 ohms per square centimeter. This high resistance represents a low permeability for most ions, since the values are nearly as high with contacts of 0.01 M NaCl, CaCl(2), LiCl, NH(4)Cl, and MgSO(4). The resistances are greatly reduced however by solutions of KCl, which is correlated with a high mobility of the K(+) ion in the protoplasm. Electrical stimulation causes a marked reduction of resistance, which may be due to exomosis of KCl. The Rockefeller University Press 1930-03-20 /pmc/articles/PMC2141060/ /pubmed/19872542 Text en Copyright © Copyright, 1930, by The Rockefeller Institute for Medical Research 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
Blinks, L. R.
THE DIRECT CURRENT RESISTANCE OF NITELLA
title THE DIRECT CURRENT RESISTANCE OF NITELLA
title_full THE DIRECT CURRENT RESISTANCE OF NITELLA
title_fullStr THE DIRECT CURRENT RESISTANCE OF NITELLA
title_full_unstemmed THE DIRECT CURRENT RESISTANCE OF NITELLA
title_short THE DIRECT CURRENT RESISTANCE OF NITELLA
title_sort direct current resistance of nitella
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2141060/
https://www.ncbi.nlm.nih.gov/pubmed/19872542
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