Optical control of a rhodopsin-based switch

A preliminary result supports the feasibility of using visible light to modulate the membrane potential of a cell. Human embryonic kidney cells (HEK293) were transfected with vertebrate rhodopsin and a gradient inward rectifying potassium (GIRK) channel. Whole cell patch clamp recordings of HEK293 cells exposed to 9-cis retinal showed that illumination increases the potassium current compared with recordings obtained in the dark. When combined with a rapid scanning device, this approach has the potential to control the activity of many neurons.