TY - JOUR
T1 - Inhibition of Na+, K+-ATPase activates swelling-induced taurine efflux in a human neuroblastoma cell line
AU - Basavappa, Srisaila
AU - Mobasheri, Ali
AU - Errington, Rachel
AU - Huang, Chiun Chien
AU - Al-Adawi, Samir
AU - Ellory, J. Clive
PY - 1998/2
Y1 - 1998/2
N2 - 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.
AB - 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.
KW - Biological Transport
KW - Brain Neoplasms/metabolism
KW - Cell Size
KW - Humans
KW - Neuroblastoma/metabolism
KW - Sodium-Potassium-Exchanging ATPase/metabolism
KW - Taurine/metabolism
KW - Tumor Cells, Cultured
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UR - http://www.scopus.com/inward/citedby.url?scp=0031890160&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1097-4652(199802)174:2<145::AID-JCP1>3.0.CO;2-O
DO - 10.1002/(SICI)1097-4652(199802)174:2<145::AID-JCP1>3.0.CO;2-O
M3 - Article
C2 - 9428800
AN - SCOPUS:0031890160
SN - 0021-9541
VL - 174
SP - 145
EP - 153
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 2
ER -