Fig. 4
Gadolinium blockade reveals critical role of stretch-activated channels in light-induced action potential generation in AMVMs. Representative action potentials recorded from Ziapin2-loaded cells before and after treatment with Gadolinium 50 µM (Gd3+) and stimulated with 20 ms- (panel a) or 200 ms-long (panel b) single light pulses. Traces have been reported as relative Vm variation to better appreciate the light-induced effect; photoexcitation is represented by the cyan shaded area. Light power density was set at 50 mW/mm2. c) Percentage of light-induced APs in Ziapin2-loaded AMVMs before and after treatment with Gd3+. d) Scatter plot of the peak hyperpolarization (ΔVm hyp Ctrl 20 ms: -3.31 ± 0.44 mV, n = 21; ΔVm hyp Gd3+ 20 ms: -2.27 ± 0.2 mV, n = 21; ΔVm hyp Ctrl 200 ms: -1.9 ± 0.27 mV, n = 13; ΔVm hyp Gd3+ 200 ms: -1.63 ± 0.17 mV, n = 19) and time-to-peak of hyperpolarization (tpeak hyp Ctrl 20 ms: 11.5 ± 0.93 ms, n = 20; tpeak hyp Gd3+ 20 ms: 11.64 ± 0.89 ms, n = 21; tpeak hyp Ctrl 200 ms: 15 ± 1.7 ms, n = 12; tpeak hyp Gd3+ 200 ms: 12.68 ± 1 ms, n = 18) in AMVMs exposed to 25 µM Ziapin2 for the above-mentioned light-stimulation protocols. Data are represented as mean ± SEM; Ctrl: N = 3. Statistical comparisons were performed using the Fisher’s exact test (panel c) and the Kruskal Wallis test (panel d)