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. 1974 Oct;242(1):35–48. doi: 10.1113/jphysiol.1974.sp010692

Steady-state contribution of the sodium pump to the resting potential of a molluscan neurone

A L F Gorman, M F Marmor
PMCID: PMC1330598  PMID: 4436827

Abstract

1. The electrogenic contribution of the Na+-K+ exchange pump to the membrane potential of the Anisodoris giant neurone (G cell) was examined under steady-state and Na+ loaded conditions.

2. The membrane potential was variable for the first 1-4 hr after impalement, but, in the absence of experimental manipulation, remained constant thereafter. The average membrane potential for ten cells maintained at 11-13 °C and measured 5-36 hr after impalement was 55·8 ± 1·0 mV (S.E. of mean).

3. Low concentrations of external ACh caused a reversible increase in membrane Na+ conductance. Brief exposure to ACh proved a fast and reversible technique to load the cell with Na+ ions, and transiently stimulate the electrogenic Na+ pump.

4. In ten cells maintained from 5 to 36 hr at 11-13° C the reduction in membrane potential produced by inhibition of the Na+ pump with ouabain was remarkably constant between cells and averaged + 9·7 mV.

5. Cells maintained under steady-state conditions (at 11-13° C) for extended periods of time were shown to be relatively insensitive to changes in temperature and to small changes in external K+.

6. It is estimated that the Na+-K+ exchange pump contributes approximately - 10 mV to the steady-state resting potential of the G cell, and that two Na+ ions are extruded for every K+ ion transported into the cell per pump cycle.

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Selected References

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

  1. Brodwick M. S., Junge D. Post-stimulus hyperpolarization and slow potassium conductance increase in Aplysia giant neurone. J Physiol. 1972 Jun;223(2):549–570. doi: 10.1113/jphysiol.1972.sp009862. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Carpenter D. O. Temperature effects on pacemaker generation, membrane potential, and critical firing threshold in Aplysia neurons. J Gen Physiol. 1967 Jul;50(6):1469–1484. doi: 10.1085/jgp.50.6.1469. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Christoffersen G. R. Steady state contribution of the Na, K-pump to the membrane potential in identified neurons of a terrestrial snail, Helix pomatia. Acta Physiol Scand. 1972 Dec;86(4):498–514. doi: 10.1111/j.1748-1716.1972.tb05352.x. [DOI] [PubMed] [Google Scholar]
  4. FRANKENHAEUSER B., HODGKIN A. L. The after-effects of impulses in the giant nerve fibres of Loligo. J Physiol. 1956 Feb 28;131(2):341–376. doi: 10.1113/jphysiol.1956.sp005467. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Garrahan P. J., Glynn I. M. The stoicheiometry of the sodium pump. J Physiol. 1967 Sep;192(1):217–235. doi: 10.1113/jphysiol.1967.sp008297. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Gorman A. L., Marmor M. F. Contributions of the sodium pump and ionic gradients to the membrane potential of a molluscan neurone. J Physiol. 1970 Nov;210(4):897–917. doi: 10.1113/jphysiol.1970.sp009248. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Gorman A. L., Marmor M. F. Long-term effect of ouabain and sodium pump inhibition on a neuronal membrane. J Physiol. 1974 Oct;242(1):49–60. doi: 10.1113/jphysiol.1974.sp010693. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Gorman A. L., Marmor M. F. Temperature dependence of the sodium-potassium permeability ratio of a molluscan neurone. J Physiol. 1970 Nov;210(4):919–931. doi: 10.1113/jphysiol.1970.sp009249. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Gorman A. L., Mirolli M. Axonal localization of an excitatory post-synaptic potential in a molluscan neurone. J Exp Biol. 1970 Dec;53(3):727–736. doi: 10.1242/jeb.53.3.727. [DOI] [PubMed] [Google Scholar]
  10. Gorman A. L., Mirolli M. The passive electrical properties of the membrane of a molluscan neurone. J Physiol. 1972 Dec;227(1):35–49. doi: 10.1113/jphysiol.1972.sp010018. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kerkut G. A., Meech R. W. The effect of ions on the membrane potential of snail neurones. Comp Biochem Physiol. 1967 Feb;20(2):411–429. doi: 10.1016/0010-406x(67)90257-5. [DOI] [PubMed] [Google Scholar]
  12. MULLINS L. J., NODA K. THE INFLUENCE OF SODIUM-FREE SOLUTIONS ON THE MEMBRANE POTENTIAL OF FROG MUSCLE FIBERS. J Gen Physiol. 1963 Sep;47:117–132. doi: 10.1085/jgp.47.1.117. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Marmor M. F. The effects of temperature and ions on the current-voltage relation and electrical characteristics of a molluscan neurone. J Physiol. 1971 Nov;218(3):573–598. doi: 10.1113/jphysiol.1971.sp009634. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Marmor M. F. The independence of electrogenic sodium transport and membrane potential in a molluscan neurone. J Physiol. 1971 Nov;218(3):599–608. doi: 10.1113/jphysiol.1971.sp009635. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Moreton R. B. An investigation of the electrogenic sodium pump in snail neurones, using the constant-field theory. J Exp Biol. 1969 Aug;51(1):181–201. doi: 10.1242/jeb.51.1.181. [DOI] [PubMed] [Google Scholar]
  16. Orkand R. K., Nicholls J. G., Kuffler S. W. Effect of nerve impulses on the membrane potential of glial cells in the central nervous system of amphibia. J Neurophysiol. 1966 Jul;29(4):788–806. doi: 10.1152/jn.1966.29.4.788. [DOI] [PubMed] [Google Scholar]
  17. Russell J. M., Brown A. M. Active transport of chloride by the giant neuron of the Aplysia abdominal ganglion. J Gen Physiol. 1972 Nov;60(5):499–518. doi: 10.1085/jgp.60.5.499. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Thomas R. C. Electrogenic sodium pump in nerve and muscle cells. Physiol Rev. 1972 Jul;52(3):563–594. doi: 10.1152/physrev.1972.52.3.563. [DOI] [PubMed] [Google Scholar]
  19. Thomas R. C. Membrane current and intracellular sodium changes in a snail neurone during extrusion of injected sodium. J Physiol. 1969 Apr;201(2):495–514. doi: 10.1113/jphysiol.1969.sp008769. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Whittam R., Ager M. E. The connexion between active cation transport and metabolism in erythrocytes. Biochem J. 1965 Oct;97(1):214–227. doi: 10.1042/bj0970214. [DOI] [PMC free article] [PubMed] [Google Scholar]

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