Skip to main content
NCBI home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1960 Sep 1;44(1):123–167. doi: 10.1085/jgp.44.1.123

Ionic Current Measurements in the Squid Giant Axon Membrane

Kenneth S Cole 1, John W Moore 1
PMCID: PMC2195082  PMID: 13694548

Abstract

The concepts, experiments, and interpretations of ionic current measurements after a step change of the squid axon membrane potential require the potential to be constant for the duration and the membrane area measured. An experimental approach to this ideal has been developed. Electrometer, operational, and control amplifiers produce the step potential between internal micropipette and external potential electrodes within 40 microseconds and a few millivolts. With an internal current electrode effective resistance of 2 ohm cm.2, the membrane potential and current may be constant within a few millivolts and 10 per cent out to near the electrode ends. The maximum membrane current patterns of the best axons are several times larger but of the type described by Cole and analyzed by Hodgkin and Huxley when the change of potential is adequately controlled. The occasional obvious distortions are attributed to the marginal adequacy of potential control to be expected from the characteristics of the current electrodes and the axon. Improvements are expected only to increase stability and accuracy. No reason has been found either to question the qualitative characteristics of the early measurements or to so discredit the analyses made of them.

Full Text

The Full Text of this article is available as a PDF (2.4 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. COLE K. S., MOORE J. W. Liquid junction and membrane potentials of the squid giant axon. J Gen Physiol. 1960 May;43:971–980. doi: 10.1085/jgp.43.5.971. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. DEL CASTILLO J., MOORE J. W. On increasing the velocity of a nerve impulse. J Physiol. 1959 Oct;148:665–670. doi: 10.1113/jphysiol.1959.sp006315. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. HODGKIN A. L., HUXLEY A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol. 1952 Aug;117(4):500–544. doi: 10.1113/jphysiol.1952.sp004764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. HODGKIN A. L., HUXLEY A. F., KATZ B. Measurement of current-voltage relations in the membrane of the giant axon of Loligo. J Physiol. 1952 Apr;116(4):424–448. doi: 10.1113/jphysiol.1952.sp004716. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. HODGKIN A. L., HUXLEY A. F. The components of membrane conductance in the giant axon of Loligo. J Physiol. 1952 Apr;116(4):473–496. doi: 10.1113/jphysiol.1952.sp004718. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. HUXLEY A. F. Ion movements during nerve activity. Ann N Y Acad Sci. 1959 Aug 28;81:221–246. doi: 10.1111/j.1749-6632.1959.tb49311.x. [DOI] [PubMed] [Google Scholar]
  7. LING G., GERARD R. W. The normal membrane potential of frog sartorius fibers. J Cell Physiol. 1949 Dec;34(3):383–396. doi: 10.1002/jcp.1030340304. [DOI] [PubMed] [Google Scholar]
  8. MARMONT G. Studies on the axon membrane; a new method. J Cell Physiol. 1949 Dec;34(3):351–382. doi: 10.1002/jcp.1030340303. [DOI] [PubMed] [Google Scholar]
  9. MOORE J. W., COLE K. S. Resting and action potentials of the squid giant axon in vivo. J Gen Physiol. 1960 May;43:961–970. doi: 10.1085/jgp.43.5.961. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. MOORE J. W. Excitation of the squid axon membrane in isosmotic potassium chloride. Nature. 1959 Jan 24;183(4656):265–266. doi: 10.1038/183265b0. [DOI] [PubMed] [Google Scholar]
  11. TASAKI I., BAK A. F. Discrete threshold and repetitive responses in the squid axon under voltage-clamp. Am J Physiol. 1958 May;193(2):301–308. doi: 10.1152/ajplegacy.1958.193.2.301. [DOI] [PubMed] [Google Scholar]
  12. TASAKI I., SPYROPOULOS C. S. Nonuniform response in the squid axon membrana under voltage-clamp. Am J Physiol. 1958 May;193(2):309–317. doi: 10.1152/ajplegacy.1958.193.2.309. [DOI] [PubMed] [Google Scholar]
  13. TAYLOR R. E. Effect of procaine on electrical properties of squid axon membrane. Am J Physiol. 1959 May;196(5):1071–1078. doi: 10.1152/ajplegacy.1959.196.5.1071. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of General Physiology are provided here courtesy of The Rockefeller University Press

RESOURCES