Potassium-dependent chloride and water transport across the seawater eel intestine

J Membr Biol. 1983;73(2):125-30. doi: 10.1007/BF01870435.

Abstract

Simultaneous measurements of net ion and water fluxes and transepithelial potential difference (PD) were made in the stripped intestine of the seawater eel, and it was examined whether Cl- was driven following electrochemical gradient for Na+ across the brush border membrane of the epithelium or not. When mucosal Na+ was completely replaced with K+, while the serosa was being bathed with normal Ringer's solution, net Cl- and water fluxes were maintained as high as those in normal Ringer's solution. After serosal Na+ was completely replaced with choline+ while the mucosa was being bathed with Na+-free KCl Ringer's solution, 80% of the original Cl- and water fluxes still persisted, indicating significant Na+-independent Cl- and water transport. These results are against a hypothesis that Cl- is driven by electrochemical gradient of Na+ across the brush border membrane. The Na+-independent Cl- and water fluxes were a saturable function of mucosal K+ concentration, suggesting K+-dependent Cl- and water transport. A possible mechanism of Cl- transport is discussed in relation to K+ transport. On the other hand, a good correlation was observed between the net Cl- and water fluxes. This suggests that water transport depends on Cl- transport system; NaCl and/or KCl cotransport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport, Active
  • Chlorides / metabolism*
  • Eels / physiology*
  • Intestinal Mucosa / physiology
  • Intestines / physiology
  • Microvilli / physiology
  • Potassium / physiology
  • Sodium / physiology
  • Water / metabolism
  • Water-Electrolyte Balance*

Substances

  • Chlorides
  • Water
  • Sodium
  • Potassium