Electrophysiological characterization of transgenic fibroblast cell lines. (A–D) Light-induced current densities (CD) and membrane potential change (ΔMP). Representative traces with increasing light intensities in colors (blue - dark green - red - light green) on the left. Statistical analysis on the right. In ChR2 fibroblasts illumination with blue light (470 nm, green bar) induces inward currents (A, original traces for: 0.01, 2.1, 4.4, 8.0 mW/mm2, n = 16) and (B) depolarization (original traces for: 0.54, 2.1, 3.7, 6.6 mW/mm2, n = 10). In ArchT-expressing fibroblasts green light (535 nm, green bar) induces outward current (C, original traces for: 0.4, 4.6, 9.2, 13 mW/mm2, n = 18) and hyperpolarization (D, original traces for 0.30, 4.4, 8.2, 11 mW/mm2, n = 13). (E–H) Influence of TGF-β1 stimulation on light-induced currents and membrane potential change. Maximal current densities of inward currents (E, n = 16 control, n = 7 TGF-β1, P = 0.40) and depolarization (F, n = 10 control, n = 5 TGF-β1, P = 0.88) in ChR2 mCherry fibroblasts. Maximal current densities (G, n = 18 control, n = 9 TGF-β1, P = 0.64) and hyperpolarization (H, n = 14 control, n = 13 TGF-β1, P = 0.32) in ArchT eYFP fibroblasts. TGF-β1, transforming growth factor-β1.
