Effects of chloride and potassium channel blockers on apoptotic cell shrinkage and apoptosis in cortical neurons

Pflugers Arch. 2004 Jun;448(3):325-34. doi: 10.1007/s00424-004-1277-2. Epub 2004 Apr 1.


K+ and Cl- homeostasis have been implicated in cell volume regulation and apoptosis. We addressed the hypothesis that K+ and Cl- efflux may contribute to apoptotic cell shrinkage and apoptotic death in cultured cortical neurons. CLC-2 and CLC-3 chloride channels were detected in cultured cortical neurons. The Cl- channel blockers 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) inhibited the outwardly rectifying Cl- current, prevented apoptotic cell shrinkage, and mildly attenuated cell death induced by staurosporine, C2-ceramide, or serum deprivation. Cl- channel blockers, however, at concentrations that prevented cell shrinkage had no significant effects on caspase activation and/or DNA fragmentation. Cell death in the presence of a Cl- channel blocker was still sensitive to blockade by the caspase inhibitor z-Val-Ala-Asp(OMe)-fluoromethyl ketone (z-VAD-fmk). Electron microscopy revealed that, although DIDS prevented apoptotic cell shrinkage, certain apoptotic ultrastructural alterations still took place in injured neurons. On the other hand, the K+ channel blocker tetraethylammonium (TEA), clofilium, or the caspase inhibitor z-VAD-fmk prevented cell shrinkage as well as caspase activation and/or DNA damage, and showed stronger neuroprotection against apoptotic alterations and cell death. The results indicate that neurons may undergo apoptotic process without cell shrinkage and imply distinct roles for Cl- and K+ homeostasis in regulating different apoptotic events.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / pharmacology
  • Animals
  • Apoptosis / drug effects*
  • Caspases / drug effects
  • Caspases / metabolism
  • Cell Size / drug effects*
  • Cells, Cultured
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / physiology
  • Chloride Channels / drug effects
  • Chloride Channels / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Membrane Potentials / drug effects
  • Mice
  • Microscopy, Electron, Transmission
  • Neurons / drug effects*
  • Neurons / metabolism
  • Neurons / ultrastructure
  • Nitrobenzoates / pharmacology
  • Patch-Clamp Techniques
  • Potassium Channel Blockers / pharmacology*
  • Potassium Channels / drug effects
  • Potassium Channels / metabolism*


  • Chloride Channels
  • Enzyme Inhibitors
  • Nitrobenzoates
  • Potassium Channel Blockers
  • Potassium Channels
  • 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
  • 5-nitro-2-(3-phenylpropylamino)benzoic acid
  • Caspases
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid