title: Channelrhodopsin2 current during the action potential: "optical AP clamp" and approximation.
abstract: The most widely used optogenetic tool, Channelrhodopsin2 (ChR2), is both light- and voltage-sensitive. A light-triggered action potential or light-driven perturbations of ongoing electrical activity provide instant voltage feedback, shaping ChR2 current. Therefore, depending on the cell type and the light pulse duration, the typically reported voltage-clamp-measured ChR2 current traces are often not a good surrogate for the ChR2 current during optically-triggered action potentials. We discuss two experimental methods to reveal ChR2 current during an action potential: an "optical AP clamp" and its approximation employing measured current-voltage curve for ChR2. The methods are applicable to voltage- and light-sensitive ion currents operating in excitable cells, e.g. cardiomyocytes or neurons.
authors: Department of Biomedical Engineering, Stony Brook University, Stony Brook, USA.
authors: Emilia
authors: E
authors: Entcheva
authors: Department of Biomedical Engineering, Stony Brook University, Stony Brook, USA.
authors: John C
authors: JC
authors: Williams
mesh_terms: D000200:Action Potentials; D002478:Cells, Cultured; D000075402:Channelrhodopsins; D006801:Humans; D008027:Light; D008962:Models, Theoretical; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques
chemical_list: D000075402:Channelrhodopsins