Real-time imaging of intracellular calcium change with simultaneous single channel recording in mammary epithelial cells.

A method of continuous image subtraction of fura-2 fluorescence made it possible to observe real-time (video rate) changes in intracellular calcium (Cai). This simple method is very useful for simultaneous measurements in electrophysiology with a system containing cells of different states. A method for synchronous recording of Cai change and single channel activity is also described. In cultured mammary epithelial cells, these methods revealed a propagating Cai signal induced by mechanical stimulation and spontaneous Cai oscillation with synchronous activation of calcium-activated potassium channels.