Skip to main content
PMC home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1972 Jun 1;59(6):720–733. doi: 10.1085/jgp.59.6.720

An Electrogenic Sodium Pump in Limulus Ventral Photoreceptor Cells

J E Brown 1, J E Lisman 1
PMCID: PMC2203198  PMID: 5025747

Abstract

A hyperpolarization can be recorded intracellularly following either a single bright light stimulus or the intracellular injection of Na+. This after-hyperpolarization is abolished by bathing in 5 x 10-6 M strophanthidin or removal of extracellular K+. Both treatments also lead to a small, rapid depolarization of the dark-adapted cell. When either treatment is prolonged, light responses can still be elicited, although with repetitive stimuli the responses are slowly and progressively diminished in size. The rate of diminution is greater for higher values of [Ca++]out; with [Ca++]out = 0.1 mM, there is almost no progressive diminution of repetitive responses produced by either K+-free seawater or strophanthidin. We propose that an electrogenic Na+ pump contributes directly to dark-adapted membrane voltage and also generates the after-hyperpolarizations, but does not directly generate the receptor potential. Inhibition of this pump leads to intracellular accumulation of sodium ions, which in turn leads to an increase in intracellular Ca++ (provided there is sufficient extracellular Ca++). This increase in intracellular calcium probably accounts for the progressive decrease in the size of the receptor potential seen when the pump is inhibited.

Full Text

The Full Text of this article is available as a PDF (876.6 KB).

Selected References

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

  1. BENOLKEN R. M. Reversal of photoreceptor polarity recorded during the graded receptor potential response to light in the eye of Limulus. Biophys J. 1961 Sep;1:551–564. doi: 10.1016/s0006-3495(61)86908-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. FUORTES M. G., YEANDLE S. PROBABILITY OF OCCURRENCE OF DISCRETE POTENTIAL WAVES IN THE EYE OF LIMULUS. J Gen Physiol. 1964 Jan;47:443–463. doi: 10.1085/jgp.47.3.443. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. 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]
  4. KERKUT G. A., THOMAS R. C. AN ELECTROGENIC SODIUM PUMP IN SNAIL NERVE CELLS. Comp Biochem Physiol. 1965 Jan;14:167–183. doi: 10.1016/0010-406x(65)90017-4. [DOI] [PubMed] [Google Scholar]
  5. KIKUCHI R., NAITO K., TANAKA I. Effect of sodium and potassium ions on the electrical activity of single cells in the lateral eye of the horseshoe crab. J Physiol. 1962 May;161:319–343. doi: 10.1113/jphysiol.1962.sp006889. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Koike H., Brown H. M., Hagiwara S. Hyperpolarization of a barnacle photoreceptor membrane following illumination. J Gen Physiol. 1971 Jun;57(6):723–737. doi: 10.1085/jgp.57.6.723. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Lisman J. E., Brown J. E. The effects of intracellular iontophoretic injection of calcium and sodium ions on the light response of Limulus ventral photoreceptors. J Gen Physiol. 1972 Jun;59(6):701–719. doi: 10.1085/jgp.59.6.701. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Lisman J. E., Brown J. E. Two light-induced processes in the photoreceptor cells of Limulus ventral eye. J Gen Physiol. 1971 Nov;58(5):544–561. doi: 10.1085/jgp.58.5.544. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Millecchia R., Mauro A. The ventral photoreceptor cells of Limulus. 3. A voltage-clamp study. J Gen Physiol. 1969 Sep;54(3):331–351. doi: 10.1085/jgp.54.3.331. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Millecchia R., Mauro A. The ventral photoreceptor cells of Limulus. 3. A voltage-clamp study. J Gen Physiol. 1969 Sep;54(3):331–351. doi: 10.1085/jgp.54.3.331. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Millecchia R., Mauro A. The ventral photoreceptor cells of Limulus. II. The basic photoresponse. J Gen Physiol. 1969 Sep;54(3):310–330. doi: 10.1085/jgp.54.3.310. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. SKOU J. C. ENZYMATIC BASIS FOR ACTIVE TRANSPORT OF NA+ AND K+ ACROSS CELL MEMBRANE. Physiol Rev. 1965 Jul;45:596–617. doi: 10.1152/physrev.1965.45.3.596. [DOI] [PubMed] [Google Scholar]
  13. Smith T. G., Stell W. K., Brown J. E. Conductance changes associated with receptor potentials in Limulus photoreceptors. Science. 1968 Oct 25;162(3852):454–456. doi: 10.1126/science.162.3852.454. [DOI] [PubMed] [Google Scholar]
  14. Smith T. G., Stell W. K., Brown J. E., Freeman J. A., Murray G. C. A role for the sodium pump in photoreception in Limulus. Science. 1968 Oct 25;162(3852):456–458. doi: 10.1126/science.162.3852.456. [DOI] [PubMed] [Google Scholar]
  15. 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]

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

RESOURCES