Stimulation of Cardiomyocyte by Light

Background: Electrical stimulation is the standard technique for exploring electrical behavior of heart muscle, but this approach has considerable technical limitations. Here we report expression of the light-activated cation channel channelrhodopsin-2 for light-induced stimulation of heart muscle in vitro.Methods: For this purpose, primary cardiomyocytes (CM) were isolated and lentiviral delivery of ChR2 (H134R) in cardiomyocytes was done by infection. A stable channelrhodopsin-2 (ChR2) expressing cardiomyocyte was developed, characterized and used. Optical imaging of voltage or calcium was performed using voltage-sensitive dye Di-8-ANEEPPS, and intracellular calcium was imaged with Fura2-AM.Results: Our result demonstrated that following blue-light illumination CM-ChR2 exhibited 26% (P < 0.05) enhancement of membrane potential as a result of depolarization compared with non-stimulated samples and 43% elevation of intracellular calcium compared with the non-stimulated group was observed.Conclusion: This method enabled precise localized stimulation and constant prolonged depolarization of cardiomyocytes resulting in alterations of membrane potential and Ca2+ homeostasis