(a) Confocal fluorescence microscopic images of A431 cells with or without EGF stimulation (100 ng/mL) for 40 min, with or without various Nox or NO synthase inhibitors, followed by washing and incubation with Peroxymycin-1 (1 μM) for 4 h. The cells were subsequently washed, fixed, stained, and imaged. All images were recorded by use of the same imaging parameters with the Alexa488 channel. (b) Cellular fluorescence intensities of A431 cells as determined by ImageJ. Error bars denote SD (n = 5). **p < 0.01.