The effects on the Schwann cell electrical potential of external ionic concentrations and of K-strophanthoside were investigated. Increasing (K)o depolarized the cell. The potential is related to the logarithm of (K)o in a quasi-linear fashion. The linear portion of the curve has a slope of 45 mv/ten-fold change in (K)o. Diminutions of (Na)o and (Cl)o produced only small variations in the potential. Calcium and magnesium can be replaced by 44 mM calcium without altering the potential. Increase of (Ca)o to 88 mM produced about 10 mv hyperpolarization. The cell was hyperpolarized by 11 mv and 4 mv within 1 min after applying K-strophanthoside at concentrations of 10-3 and 10-5 M, respectively. No variations of cellular potassium, sodium, or chloride were observed 3 min after applying the glycoside. The hyperpolarization caused by 10-3 M K-strophanthoside was not observed when (K)o was diminished to 1 or 0.1 mM or was increased to 30 mM. At a (K)o of 30 mM, 10-2 M strophanthoside was required to produce the hyperpolarizing effect. In high calcium, the cell was further hyperpolarized by the glycoside. The initial hyperpolarization caused by the glycoside was followed by a gradual depolarization and a decrease of the cellular potassium concentration. The results indicate that the Schwann cell potential of about -40 mv is due to ionic diffusion, mainly of potassium, and to a cardiac glycoside-sensitive ion transport process.
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1 January 1968
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January 01 1968
Nature of the Schwann Cell Electrical Potential : Effects of the external ionic concentrations and a cardiac glycoside
Jorge Villegas,
Jorge Villegas
From Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
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Raimundo Villegas,
Raimundo Villegas
From Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
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Máximo Giménez
Máximo Giménez
From Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
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Jorge Villegas
From Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
Raimundo Villegas
From Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
Máximo Giménez
From Centro de Biofísica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
Received:
June 21 1967
Online ISSN: 1540-7748
Print ISSN: 0022-1295
Copyright © 1968 by The Rockefeller University Press
1968
J Gen Physiol (1968) 51 (1): 47–64.
Article history
Received:
June 21 1967
Citation
Jorge Villegas, Raimundo Villegas, Máximo Giménez; Nature of the Schwann Cell Electrical Potential : Effects of the external ionic concentrations and a cardiac glycoside . J Gen Physiol 1 January 1968; 51 (1): 47–64. doi: https://doi.org/10.1085/jgp.51.1.47
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