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.
|Number of pages||9|
|Journal||Journal of Cellular Physiology|
|Publication status||Published - Feb 1998|
ASJC Scopus subject areas
- Clinical Biochemistry
- Cell Biology