title: Monitoring ion activities in and around cells using  ion-selective liquid-membrane microelectrodes.
abstract: Determining the effective concentration (i.e., activity) of ions in and around living cells is important to our understanding of the contribution of those ions to cellular function. Moreover, monitoring changes in ion activities in and around cells is informative about the actions of the transporters and/or channels operating in the cell membrane. The activity of an ion can be measured using a glass microelectrode that includes in its tip a liquid-membrane doped with an ion-selective ionophore. Because these electrodes can be fabricated with tip diameters that are less than 1 μm, they can be used to impale single cells in order to monitor the activities of intracellular ions. This review summarizes the history, theory, and practice of ion-selective microelectrode use and brings together a number of classic and recent examples of their usefulness in the realm of physiological study.
authors: Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. sxl271@case.edu
authors: Seong-Ki
authors: SK
authors: Lee
authors: Walter F
authors: WF
authors: Boron
authors: Mark D
authors: MD
authors: Parker
mesh_terms: D000818:Animals; D002138:Calibration; D002462:Cell Membrane / Q000378:metabolism*; D017736:Ion-Selective Electrodes; D007476:Ionophores; D007477:Ions / Q000378:metabolism*; D008839:Microelectrodes
chemical_list: D007476:Ionophores; D007477:Ions