Glass Micro-Electrodes for Measuring Intracellular Activities of Sodium and Potassium

RECENTLY, Eisenman, Rudin and Casby1 reported on the preparation of cation-sensitive glasses and indicated their potential usefulness as electrodes for biological studies. Friedman et al.2,3 adapted such electrodes for measuring continuously the plasma sodium of a rabbit and dog. Caldwell4 demonstrated that pH glass electrodes can be constructed on a microscale for measuring intracellular pH. The present report concerns construction of micro-electrodes for intracellular measurement of sodium and potassium activities.