Abstract
Light-gated ion channels allow modifying transmembrane ion fluxes and consequently,the intracellular distribution of ions without applying electric fields or introducing stimulating electrodes. Channelrhodopsyn is a Na+ and Ca2+ permeable cation channel, which opens in response to illumination at wavelengths of 460-490 nm. The influx of Na+ and Ca2+ depolarizes the cells and results in an increase of the intracellular Ca-concentration.Increased intracellular Ca-levels promote secretion of cellular material and can increase cell motility.
These events can be recorded by OWLS assays detecting changes in the overall material deposition by cells.