Calcium imaging techniques in cell lines

Calcium imaging is a scientific technique which is  designed to measure the intracellular free calcium  concentration (Ca2+) in an isolated cell or tissue.  Calcium imaging techniques utilizes fluorescent  molecules so called Ca2+ indicators that can respond to  the binding of Ca2+ ions by changing  heir fluorescence  properties. Binding of a Ca2+ ion to a fluorescent  indicator molecule leads to either an elevation in its  fluorescence intensity or emission/excitation  wavelength shift.  Two main classes of calcium indicators are  chemical indicators and genetically encoded calcium  indicators. Chemical indicators are small molecules that  can bind calcium ions. This group of indicators includes  Fura-2, Fluo-3, Fluo-4, Rhod-2. These dyes are often  used with acetoxymethyl esters, in order to render the  molecule lipophilic and to allow easy entrance into the  cell. Genetically encoded indicators do not need to be  loaded onto cells, instead the genes encoding for these  proteins can be easily transfected to cells. These  indicators are fluorescent proteins derived from green  fluorescent protein (GFP).  The time-scan mode of laser confocal microscopy  is often used for calcium imaging. Intracellular Ca 2+ ions generate versatile  intracellular signals that control  key functions in all types of cells. In sensory neurons  Ca2+ signals are associated with pain transmission.