Ca2+ Imaging of Glia

Glial cells are besides neurons the second major cell type of nervous systems and are either of neuroectodermal (macroglia) or mesodermal (microglia) origin. As electrically non-excitable cells, they employ calcium signals in response to most external stimuli, which initiate cellular activity. A variety of techniques are described here, which have been developed to monitor cellular calcium in different glial cell preparations from cell culture, acute tissue slices to in vivo measurements. New optical innovations in the last two decades, as e.g. generations of new calcium-sensitive fluorescent dyes, genetically-encoded calcium sensors and multiple applications of laser scanning microscopy have allowed novel experimental approaches and have provided important results for our understanding of nervous systems. The study of calcium signalling in glial cells from both vertebrate and invertebrate preparations has also significantly contributed to our understanding of the significance of cytosolic calcium elevations in different cell types and subcellular compartments.