Inhibition of Na+, K+-ATPase activates swelling-induced taurine efflux in a human neuroblastoma cell line

S Basavappa, A Mobasheri, R Errington, C C Huang, S Al-Adawi, J C Ellory

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The Na+ pump (Na+, K+-ATPase) has been implicated in the regulation of many cellular functions, including cell volume regulation. The effects of inhibiting Na+ pump activity on cell volume and taurine efflux were evaluated in the human neuroblastoma cell line CHP-100. Cell volume changes monitored with the Coulter Multisizer technique and confocal microscopy showed that neuroblastoma cells exposed to ouabain swelled by 22 +/- 4% (n = 5). The rapid cell swelling was followed by regulatory volume decrease (RVD). In cells treated with ouabain, 14C-taurine efflux increased by 183 +/- 11% compared with controls. However, cells exposed simultaneously to ouabain and hypoosmotic solution resulted in a 14C-taurine efflux of 207 +/- 18%. Western blot and immunofluorescence microscopy with specific monoclonal antibodies for the catalytic alpha isoforms of Na+, K+-ATPase demonstrated high levels of the ubiquitously expressed alpha1 and the neuronal-specific alpha3. Ouabain-binding data showed that CHP-100 cells express approximately 3 x 10(5) pump units/cell. The present data indicate that efflux of taurine may be involved during volume recovery subsequent to blockade of Na+, K+-ATPase in CHP-100 cells.

Original languageEnglish
Pages (from-to)145-53
Number of pages9
JournalJournal of Cellular Physiology
Issue number2
Publication statusPublished - Feb 1998


  • Biological Transport
  • Brain Neoplasms/metabolism
  • Cell Size
  • Humans
  • Neuroblastoma/metabolism
  • Sodium-Potassium-Exchanging ATPase/metabolism
  • Taurine/metabolism
  • Tumor Cells, Cultured

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