cAMP measurements with FRET-based sensors in excitable cells.

The development of FRET (fluorescence resonance energy transfer)-based sensors for measuring cAMP has opened the door to sophisticated insights into single-cell cAMP dynamics. cAMP can be measured in distinct cell populations and even in distinct microdomains within cells. However, there is still only limited information on cAMP dynamics in excitable cells, particularly as a function of the activity of voltage-gated Ca2+ channels. A major reason for this is the pH shifts that can occur in excitable cells and their effects on fluorescent proteins.