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

✍ Scribed by Srisaila Basavappa; Ali Mobasheri; Rachel Errington; Chiun-Chien Huang; Samir Al-Adawi; J. Clive Ellory

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 416 KB
• Volume: 174
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199802)174:2<145::aid-jcp1>3.0.co;2-o

✦ Synopsis

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 Å 5). The rapid cell swelling was followed by regulatory volume decrease (RVD). In cells treated with ouabain, 14 C-taurine efflux increased by 183 { 11% compared with controls. However, cells exposed simultaneously to ouabain and hypoosmotic solution resulted in a 14 C-taurine efflux of 207 { 18%. Western blot and immunofluorescence microscopy with specific monoclonal antibodies for the catalytic a isoforms of Na / , K / -ATPase demonstrated high levels of the ubiquitously expressed a1 and the neuronal-specific a3. Ouabain-binding data showed that CHP-100 cells express Ç3 1 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.