Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Saline-filled Micro-electrodes in Relation to Membrane Potential Measurement in Freshwater Protozoa


THE measurement of membrane potentials in fresh-water protozoa is complicated by the presence of junction potentials existing between the micro-electrode and the medium. These seem to be associated with the fine dimensions of the electrode, coupled with a steep ionic gradient between the contents of the glass electrode and the medium. Adrian1 was the first to consider in detail the problem of electrode tip potentials and its relationship to membrane potentials. He noted that potentials in frog muscle cells are often increased when the tips of saline-filled micro-electrodes break. Bingley2 describes a technique for reducing electrode resistance and tip potential before recording membrane potentials in amoebae. It is necessary to pre-treat micro-electrodes filled with 3.0 M potassium chloride by passing them through agar gel. Potentials were only successfully recorded from amoebae with micro-electrodes which had resistances less than 15.0 M ohm but more than 4.0 M ohm. Above the upper limit, negative tip potentials were too high and no potential was recorded; below, the amoebae sustained damage with a lowering of membrane potential.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others


  1. Adrian, R. H., J. Physiol., 133, 631 (1956).

    Article  CAS  Google Scholar 

  2. Bingley, M. S. (in the press).

  3. Chalkley, H. W., Science, 71, 442 (1930).

    Article  ADS  CAS  Google Scholar 

  4. Bingley, and Thompson, J. Theor. Biol., 2, 16 (1962).

    Article  CAS  Google Scholar 

  5. Eisenman, G., Rudin, and Casby, Science, 126, 831 (1957).

    Article  ADS  CAS  Google Scholar 

  6. Brown, R. C., Mechanics and Properties of Matter, 205 (1956).

    Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and permissions

About this article

Cite this article

BINGLEY, M. Saline-filled Micro-electrodes in Relation to Membrane Potential Measurement in Freshwater Protozoa. Nature 202, 1218–1219 (1964).

Download citation

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing