Activation by acidic pH of CLC-7 expressed in oocytes from Xenopus laevis

Biochem Biophys Res Commun. 2002 Feb 22;291(2):421-4. doi: 10.1006/bbrc.2002.6462.


ClC chloride channels are important in diverse physiological functions such as transepithelial transport, cell volume regulation, excitability, and acidification of intracellular organelles. We have investigated the expression of CLC-7 in oocytes from Xenopus laevis with the two electrode voltage clamp technique and Western blot analysis. Using a specific antibody against CLC-7, we found an approximately 80 kDa protein in oocytes, previously injected with CLC-7-cRNA. In voltage clamp experiments on ClC-7-cRNA-injected oocytes, no current changes were detected at normal pH (7.4). However, acidification of the Ringer solution to pH values between 6 and 4 revealed strong currents which reversed at about -15 mV (30 mV positive to the normal resting potential) and showed strong outward rectification. We therefore suggest that ClC-7 in oocytes is a functional chloride current at acidic pH. Since ClC-7 is also found in neuronal tissues and was upregulated in a rat pain model, we suggest a role of CLC-7 also for nociception and pain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Chloride Channels / metabolism*
  • Electric Conductivity
  • Hydrogen-Ion Concentration*
  • Oocytes / metabolism
  • Patch-Clamp Techniques
  • Rats
  • Xenopus laevis


  • Chloride Channels
  • Clcn7 protein, rat