Similar to A-23187, 4-Bromo A-23187 is used for in situ calibrations of fluorescent Ca2 indicators to equilibrate intracellular and extracellular calcium concentrations and to allow Mn2 to enter cells to quench indicator fluorescence. However, since 4-bromo A-23187 is nonfluorescent, it is preferred over the blue fluorescent A-23187 for calibrations of UV-excited Ca2 indicators such as Indo-1 and Fura-2 in order to keep background fluorescence to a minimum.    White solid soluble in DMSO or EtOH  Store at 4°C  C29H36BrN3O6  MW: 602.52  [76455-48-6]