Direct measurement of specific membrane capacitance in neurons

Luc J. Gentet, Greg J. Stuart, John D. Clements*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    336 Citations (Scopus)

    Abstract

    The specific membrane capacitance (C(m)) of a neuron influences synaptic efficacy and determines the speed with which electrical signals propagate along dendrites and unmyelinated axons. The value of this important parameter remains controversial. In this study, C(m) was estimated for the somatic membrane of cortical pyramidal neurons, spinal cord neurons, and hippocampal neurons. A nucleated patch was pulled and a voltage-clamp step was applied. The exponential decay of the capacitative charging current was analyzed to give the total membrane capacitance, which was then divided by the observed surface area of the patch. C(m) was 0.9 μF/cm2 for each class of neuron. To test the possibility that membrane proteins may alter C(m), embryonic kidney cells (HEK-293) were studied before and after transfection with a plasmid coding for glycine receptor/channels. The value of C(m) was indistinguishable in untransfected cells and in transfected cells expressing a high level of glycine channels, indicating that differences in transmembrane protein content do not significantly affect C(m). Thus, to a first approximation, C(m) may be treated as a 'Biological constant' across many classes of neuron.

    Original languageEnglish
    Pages (from-to)314-320
    Number of pages7
    JournalBiophysical Journal
    Volume79
    Issue number1
    DOIs
    Publication statusPublished - Jul 2000

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