Cell function markers and methods

• Book ID: 102814708
• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 658 KB
• Volume: 18
• Category: Article
• ISSN: 0196-4763
• DOI: 10.1002/cyto.990180508

✦ Synopsis

Hyperthermia causes transient alterations in intracellular pH in mammalian cells. However, few reports have shown an effect of hyperthermia on other ions. Recently, a new sodium indicator, Sodium Green, was developed which can he used with flow cytometry to measure intracellular sodium (Na+,). Chinese hamster ovary cells were loaded with Sodium Green Tetraacetate and either heated in suspension or calibrated using gramicidin as an ionophore. The ratio of integral green fluorescence (IGFL) to forward angle light scatter (FALS) was measured to partially normalize for cell size variations in the cell population. The mean IGFLlFALS ratio was converted into Na+, concentration using three known calibration samples and the Grynkiewicz equation. Cells heated at 42" or 45" C for 30 min had a 4-fold decrease in Na', below unheated control values when measured immediately after heating. The magnitude of this reduction in Na+, depended on both time and temperature. The Na+, recovered in a time-dependent fashion to 75 % of control levels by 30 min after heating. When cells were heated at 45" C for 30 min in the presence of either 1 mM ouabain or 0.5 mM amiloride, only a 2-fold reduction in Na+, was observed. Since ouabain inhibits the Na+/K+ ATPase pump and amiloride inhihitsthe Na+/H+ antiporter, these ion channels are probably involved in the heat-induced decrease in Na+,.