Skip to main content
PMC home page
The Journal of General Physiology logoLink to The Journal of General Physiology
. 1972 Aug 1;60(2):181–201. doi: 10.1085/jgp.60.2.181

Sodium Flux in Necturus Proximal Tubule under Voltage Clamp

Kenneth R Spring 1, Charles V Paganelli 1
PMCID: PMC2226065  PMID: 5049078

Abstract

Na transport and electrical properties of Necturus renal proximal tubules were analyzed, in vivo, by a voltage clamp method which utilizes an axial electrode in the tubule lumen for passage of current and simultaneous determination of net fluid (or Na) flux by the split droplet method. When the average spontaneous transepithelial potential difference of –8 mv (lumen negative) was reduced to zero by current passage, net Na flux doubled from a mean of 107 to 227 pmoles/cm2 per sec. The relationship between flux and potential over the range –25 to +10 mv was nonlinear, with flux equilibrium at –15 mv and droplet expansion at more negative values. Calculated Na permeability at flux equilibrium was 7.0 x 10–6 cm/sec. Voltage transients, similar to those caused by intraepithelial unstirred layers, were observed at the end of clamping periods. Tubular electrical resistance measured by brief square or triangle wave pulses (<100 msec) averaged 43 ohm cm2. The epithelial current-voltage relationship was linear over the range –100 to +100 mv, but displayed marked hysteresis during low frequency (<0.04 Hz) triangle wave clamps. The low transepithelial resistance and large opposing unidirectional ion fluxes suggest that passive ionic movements occur across extracellular shunt pathways, while the voltage transients and current-voltage hysteresis are consistent with the development of a local osmotic gradient within epithelium.

Full Text

The Full Text of this article is available as a PDF (1.2 MB).

Selected References

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

  1. Bentzel C. J., Anagnostopoulos T., Pandit H. Necturus kidney: its response to effects of isotonic volume expansion. Am J Physiol. 1970 Jan;218(1):205–213. doi: 10.1152/ajplegacy.1970.218.1.205. [DOI] [PubMed] [Google Scholar]
  2. Bentzel C. J., Parsa B., Hare D. K. Osmotic flow across proximal tubule of Necturus: correlation of physiologic and anatomic studies. Am J Physiol. 1969 Aug;217(2):570–580. doi: 10.1152/ajplegacy.1969.217.2.570. [DOI] [PubMed] [Google Scholar]
  3. Boulpaep E. L. Permeability changes of the proximal tubule of Necturus during saline loading. Am J Physiol. 1972 Mar;222(3):517–531. doi: 10.1152/ajplegacy.1972.222.3.517. [DOI] [PubMed] [Google Scholar]
  4. COLE K. S., KISHIMITO U. Platinized silver chloride electrode. Science. 1962 May 4;136(3514):381–382. doi: 10.1126/science.136.3514.381. [DOI] [PubMed] [Google Scholar]
  5. EIGLER F. W. Short-circuit current measurements in proximal tubule of Necturus kidney. Am J Physiol. 1961 Jul;201:157–163. doi: 10.1152/ajplegacy.1961.201.1.157. [DOI] [PubMed] [Google Scholar]
  6. GERTZ K. H. [Transtubular sodium chloride transport and permeability for nonelectrolytes in the proximal and distal convolution of the rat kidney]. Pflugers Arch Gesamte Physiol Menschen Tiere. 1963;276:336–356. [PubMed] [Google Scholar]
  7. GIEBISCH G. Electrical potential measurements on single nephrons of Necturus. J Cell Physiol. 1958 Apr;51(2):221–239. doi: 10.1002/jcp.1030510208. [DOI] [PubMed] [Google Scholar]
  8. GIEBISCH G. Measurements of electrical potential differences on single nephrons of the perfused Necturus kidney. J Gen Physiol. 1961 Mar;44:659–678. doi: 10.1085/jgp.44.4.659. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. GIEBISCH G., WINDHAGER E. E. Measurement of chloride movement across single proximal tubules of Necturus kidney. Am J Physiol. 1963 Mar;204:387–391. doi: 10.1152/ajplegacy.1963.204.3.387. [DOI] [PubMed] [Google Scholar]
  10. Howell B. J., Baumgardner F. W., Bondi K., Rahn H. Acid-base balance in cold-blooded vertebrates as a function of body temperature. Am J Physiol. 1970 Feb;218(2):600–606. doi: 10.1152/ajplegacy.1970.218.2.600. [DOI] [PubMed] [Google Scholar]
  11. Nakajima K., Clapp J. R., Robinson R. R. Limitations of the shrinking-drop micropuncture technique. Am J Physiol. 1970 Aug;219(2):345–357. doi: 10.1152/ajplegacy.1970.219.2.345. [DOI] [PubMed] [Google Scholar]
  12. OKEN D. E., WHITTEMBURY G., WINDHAGER E. E., SOLOMON A. K. Single proximal tubules of Necturus kidney. V. Unidirectional sodium movement. Am J Physiol. 1963 Mar;204:372–376. doi: 10.1152/ajplegacy.1963.204.3.372. [DOI] [PubMed] [Google Scholar]
  13. Patlak C. S., Goldstein D. A., Hoffman J. F. The flow of solute and solvent across a two-membrane system. J Theor Biol. 1963 Nov;5(3):426–442. doi: 10.1016/0022-5193(63)90088-2. [DOI] [PubMed] [Google Scholar]
  14. Scott W. N., Maude D. L., Shehadeh I., Solomon A. K. Transtubular movement of albumin in Necturus kidney. Am J Physiol. 1966 Oct;211(4):1039–1042. doi: 10.1152/ajplegacy.1966.211.4.1039. [DOI] [PubMed] [Google Scholar]
  15. USSING H. H., ZERAHN K. Active transport of sodium as the source of electric current in the short-circuited isolated frog skin. Acta Physiol Scand. 1951 Aug 25;23(2-3):110–127. doi: 10.1111/j.1748-1716.1951.tb00800.x. [DOI] [PubMed] [Google Scholar]
  16. WHITTEMBURY G., SUGINO N., SOLOMON A. K. Ionic permeability and electrical potential differences in Necturus kidney cells. J Gen Physiol. 1961 Mar;44:689–712. doi: 10.1085/jgp.44.4.689. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. WHITTEMBURY G., WINDHAGER E. E. Electrical potential difference measurements in perfused single proximal tubules of Necturus kidney. J Gen Physiol. 1961 Mar;44:679–687. doi: 10.1085/jgp.44.4.679. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. WINDHAGER E. E., GIEBISCH G. Comparison of short-circuit current and net water movement in single perfused proximal tubules of rat kidneys. Nature. 1961 Sep 16;191:1205–1207. doi: 10.1038/1911205a0. [DOI] [PubMed] [Google Scholar]
  19. WINDHAGER E. E., GIEBISCH G. ELECTROPHYSIOLOGY OF THE NEPHRON. Physiol Rev. 1965 Apr;45:214–244. doi: 10.1152/physrev.1965.45.2.214. [DOI] [PubMed] [Google Scholar]

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

RESOURCES