Techniques for measuring and manipulating free Ca2+ in the cytosol and organelles of neutrophils

Ca2+ signalling in neutrophils is important for triggering and coordinating the behaviour of neutrophils. Fluorescent probes for cytosolic free Ca2+ concentration, e.g., fura2 and fluo3, have been widely used in neutrophils. These probes can be used to monitor Ca2+ in the cytosol, the nucleus, near the plasma membrane and theoretically within Ca2+ storage organelles. The longer wavelength indicators, e.g., fluo3 and calcium green, can be used confocally to monitor subcellular Ca2+ changes in the cytosol of neutrophils and in the nucleus. Confocal techniques also permit "impossible views'' imaging of Ca2+ and newer scanning techniques promise very fast temporal resolution. Techniques using chlortetracycline (CTC) and DiOC(6)(3) are also described for monitoring the position of Ca2+ storage sites in neutrophils and for manipulating their activity. Thus, in this review, a spectrum of new land older) optical techniques are presented which are useful for measuring, monitoring and manipulating cytosolic free Ca2+ concentration and Ca2+ storage in neutrophils. With these techniques, it is hoped that more insight will be gained into both the mechanism of and the consequences of Ca2+ signalling in neutrophils. (C) 1999 Elsevier Science B.V. All rights reserved.