Capturing single L-type Ca2Â + channel function with optics

► Advances of imaging technology have allowed optical analysis of L-type Ca2 + channels with high resolution. ► L-type Ca2 + channel activity varies regionally throughout the plasmalemma of excitable cells. ► A subpopulation of L-type Ca2 + channels can operate in a coupled manner with profound implications in health and disease. ► Emerging Ca2 + indicators are promising developments in understanding nano- and microdomain Ca2 + signals.