Figure 2. Activation of TRPA1 channels by chemical DNFB in calcium fluorescent assay. (a, b, c and d) Normalized increase of intracellular Ca2+ levels in response to different concentrations of DNFB (3-300 μM) or channel agonists of AITC (300 µM) for TRPA1 (a), capsaicin (1 µM) for TRPV1 (b), 2-APB (200 µM) for TRPV3 (c) and GSK101 (0.1 µM) for TRPV4 (d) (n = 6).