RT Journal Article
SR Electronic
T1 Exclusive potassium dependence of the membrane potential in cultured mouse oligodendrocytes
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 500
OP 505
DO 10.1523/JNEUROSCI.03-03-00500.1983
VO 3
IS 3
A1 H Kettenmann
A1 U Sonnhof
A1 M Schachner
YR 1983
UL http://www.jneurosci.org/content/3/3/500.abstract
AB Membrane potential, conductance, and intracellular potassium concentration were measured in oligodendrocytes in 3- to 10-week-old cultures of embryonic mouse spinal cord. After intracellular recording the cells were first injected with Lucifer Yellow and then stained by immunofluorescence using rhodamine-labeled monoclonal antibody 01 specific for oligodendrocyte cell surfaces. The membrane potential of these identified oligodendrocytes was in mV -66 +/- 4.3 SD; it could be reversibly reduced almost to zero by the addition of ouabain. Changes in external K+ but not Na+, Ca++, or Cl- changed the membrane potential. A 10-fold increase in extracellular potassium concentration ([K+]0) depolarized the cell by about 52 mV. This is less than the 61 mV predicted by the Nernst equation for a K+ electrode assuming a constant intracellular potassium concentration ([K+]i). However, when [K+]i was measured with an ion-selective electrode during the increase in [K+]0 it was found to rise. The Nernst equation for K+ accurately predicts the oligodendrocyte membrane potential when the increase in [K+]i is taken into account. Oligodendrocytes may be described as accurate K+ electrodes with a variable reference solution.