Patch clamp

Action potentials (APs) were measured in current-clamp mode using the ruptured-patch clamp configuration with a specific pipette solution (Table 1) (Coppini et al., 2013; Coppini et al., 2019). The experimental temperature was 36°C ± 2°C. APs were elicited with short depolarizing stimuli (<3 ms) at different frequency of stimulation (0.2, 0.5 and 1 Hz, 1 min at each frequency). Patch clamp recordings were performed before and after addition of E4031(5 µM). Main chamber solution is frequently cleaned by a fast-rate heated perfusion end placed at the chamber’s side, that allows fast washout of chemicals in the bath.