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

Srisaila Basavappa, Ali Mobasheri, Rachel Errington, Chiun Chien Huang, Samir Al-Adawi, J. Clive Ellory

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Abstract

The Na+ pump (Na+, K+ -ATPase) has been implicated in the 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 α isoforms of Na+, K+ -ATPase demonstrated high levels of the ubiquitously expressed α1 and the neuronal- specific α3. Ouabain-binding data showed that CHP-100 cells express ~3 x 105 pump units/cell. The present data indicate the efflux of taurine maya be involved during volume recovery subsequent to blockade of Na+, K+ -ATPase in CHP-100 cells.

Original languageEnglish
Pages (from-to)145-153
Number of pages9
JournalJournal of Cellular Physiology
Volume174
Issue number2
DOIs
Publication statusPublished - Feb 1998

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ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

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