Figure 3.

Whole-cell patch clamp and sharp electrode measurements of ReaChR photocurrents and membrane potential responses, and computational light penetration simulations at different excitation wavelengths. (A and B) Relative ReaChR I_peak (A) and I_plateau (B) amplitudes measured at −90 mV holding potentials upon illumination with 567 or 617 nm light compared to 470 nm light as the index (500 ms, 1 mW/mm²). Each dot represents the paired results of an individual cell (n=6 cells from four hearts). For the light pulses of 470 nm, the single dots represent averaged values. (C) ReaChR plateau potentials (V_plateau) measured at the end of a 500 ms light pulse (1 mW/mm²) for 470, 567, and 617 nm light. Each dot represents the results of an individual cell (n=6 cells from four hearts). (D) Representative sharp electrode measurements of a ReaChR-expressing ventricular tissue sample from a TAC rat showing sustained depolarization illumination for 500 ms with blue (λ=470 nm), lime (λ=567 nm), or red (λ=617 nm) light of various intensities. All recordings are from the same ventricular spot. (E) Computational simulations of propagation of 470, 567, and 617 nm light through rat myocardium.