Calcium imaging with chemiluminescence

This review updates the imaging of free cytosolic calcium with the chemilum inescent aequorins. Basic principles of chemiluminescence are discussed and the biochemistry of aequorins is briefly described. The review provides pr actical tips on handling and microinjecting aequorins and describes availab le ultra low light imaging systems. It is argued that aequorin-based calciu m imaging is the method of choice for exploratory studies, since it is extr emely sensitive, can detect a broad range of calcium concentrations, and al lows for continuous recording during long periods of time. However, fluores cent methods are needed to attain high spatial resolution. (C) 1999 Wiley-L iss, Inc.