Figure 1.

Ziapin2 mediates a light-evoked membrane voltage modulation in hiPSC-CMs

(A) Representative whole-cell current-clamp traces recorded in cells loaded with either vehicle (DMSO, in black) or Ziapin2 (blue) and stimulated with 20 ms- (left) or 200 ms-long (right) single light pulses. Photoexcitation is represented by the cyan shaded area. Light power density, 80 mW/mm². The membrane potential modulation can be appreciated at a faster timescale in the inset of each panel.

(B) Scatterplots of the peak hyperpolarization (left) and depolarization (right) changes in hiPSC-CMs exposed to Ziapin2 (5 μM in sky blue, 25 μM in teal) or DMSO for the above-mentioned light-stimulation protocols. n > 18 for 5 μM and 25 μM Ziapin2-loaded cells and n = 20 for DMSO-treated hiPSC-CMs. V_m values have been reported as relative variation to better appreciate the light-induced effect; however, no significant changes were detected in the resting membrane potential values (Ziapin2 5 μM Vm = -42.4 ± 3.9 mV; Ziapin2 25 μM Vm = -42.8 ± 2.6 mV; DMSO Vm = -37 ± 4.4 mV). The experiments were carried out at room temperature (24°C). Data were collected from three independent differentiations and are represented as mean ± SEM ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001 and ∗∗∗∗p < 0.0001.