Fig. 2.

US triggers Ca²⁺ transients in N₂A. (A) Confocal images of N₂A cells before, immediately or 5 min after receiving US irradiation in bright field, Fluo-4 AM (green), PI staining (red) and merge model. The fluorescence intensity of Fluo-4 reflects the concentration of intracellular calcium. PI can stain dead cells red due to cell membrane destruction. Scale bar, 100 μm. (B) Significantly enhanced Ca²⁺ fluorescence signals (dF/F₀) could be immediately observed in N₂A cells in response to US stimulation and trended to decay after 5 min. (C) Average maximum dF/F₀ mean fluorescence intensity in control and US-stimulated cells. (C) Data are expressed as mean ± SEM and analyzed by two-tail unpaired Student t test. ***P < 0.0001 vs Control. (n = 46 cells from 3 slices). n represents the number of cells with the enhanced Ca²⁺ signals. Acoustic pressure is 0.17 MPa, T1 = 500 μs, T2 = 1 ms, T3 = 300 ms, T4 = 3 s, total time is 10 s. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)