Functional cardiac imaging by random access microscopy.

Advances in the development of voltage sensitive dyes and Ca(2+) sensors in combination with innovative microscopy techniques allowed researchers to perform functional measurements with an unprecedented spatial and temporal resolution. At the moment, one of the shortcomings of available technologies is their incapability of imaging multiple fast phenomena while controlling the biological determinants involved. In the near future, ultrafast deflectors can be used to rapidly scan laser beams across the sample, performing optical measurements of action potential and Ca(2+) release from multiple sites within cardiac cells and tissues. The same scanning modality could also be used to control local Ca(2+) release and membrane electrical activity by activation of caged compounds and light-gated ion channels. With this approach, local Ca(2+) or voltage perturbations could be induced, simulating arrhythmogenic events, and their impact on physiological cell activity could be explored. The development of this optical methodology will provide fundamental insights in cardiac disease, boosting new therapeutic strategies, and, more generally, it will represent a new approach for the investigation of the physiology of excitable cells.