Skip to main content
NCBI home page
Biophysical Journal logoLink to Biophysical Journal
. 1960 Nov;1(2):161–202. doi: 10.1016/s0006-3495(60)86882-8

Analysis of Certain Errors in Squid Axon Voltage Clamp Measurements

Robert E Taylor, John W Moore, Kenneth S Cole
PMCID: PMC1366328  PMID: 13775643

Abstract

Localized membrane current and potential measurements were made on the squid giant axon in voltage clamp experiments. Spatial control of potential was impaired by the use of axial current supplying electrodes with surface resistance greater than 20 ohms for a centimeter length of axon. No region of membrane which was indeed subjected to a potential step showed more than one inward current peak. Other patterns were results of space clamp failure. Membrane current and potential patterns during space clamp failure were approximately reproduced in computations on a model containing two membrane patches obeying the equations of Hodgkin and Huxley. Non-uniformities in the axon or electrodes are not necessary for non-uniform electrical behavior. An extension of the core conductor model which includes the axial wire and external solution has been analyzed. The space constant of electrotonic spread is less than 0.5 mm with a usable electrode. Errors of about 5 per cent are introduced by ignoring the external solution. Resistance between the membrane and the control electrodes reduces the control and a few ohm cm2 could lead to serious errors in interpretation.

Full text

PDF
161

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. Ionic current measurements in the squid giant axon membrane. J Gen Physiol. 1960 Sep;44:123–167. doi: 10.1085/jgp.44.1.123. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. DODGE F. A., FRANKENHAEUSER B. Membrane currents in isolated frog nerve fibre under voltage clamp conditions. J Physiol. 1958 Aug 29;143(1):76–90. doi: 10.1113/jphysiol.1958.sp006045. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. FITZHUGH R. Thresholds and plateaus in the Hodgkin-Huxley nerve equations. J Gen Physiol. 1960 May;43:867–896. doi: 10.1085/jgp.43.5.867. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. FRANKENHAEUSER B., HODGKIN A. L. The action of calcium on the electrical properties of squid axons. J Physiol. 1957 Jul 11;137(2):218–244. doi: 10.1113/jphysiol.1957.sp005808. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. HAGIWARA S., SAITO N. Voltage-current relations in nerve cell membrane of Onchidium verruculatum. J Physiol. 1959 Oct;148:161–179. doi: 10.1113/jphysiol.1959.sp006279. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. 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]
  7. 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]
  8. TASAKI I., BAK A. F. Current-voltage relations of single nodes of Ranvier as examined by voltage-clamp technique. J Neurophysiol. 1958 Mar;21(2):124–137. doi: 10.1152/jn.1958.21.2.124. [DOI] [PubMed] [Google Scholar]
  9. 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]

Articles from Biophysical Journal are provided here courtesy of The Biophysical Society

RESOURCES