Suppression of AITC-induced current density in DRG neurons by artemin. (A, B): Representative traces show TRPA1 currents produced by AITC application (300 μM, 1 min) in the absence (A) or presence (B) of artemin (100 ng/ml). AITC was applied for 1 min after artemin administration for 2 min. (C): Bar graph shows the effect of artemin on AITC activated current density (pA/pF). Numbers in parenthesis indicate cells tested. * p < 0.05 versus control (absence of artemin), unpaired t-test. (D): Concentration-response curves for AITC-induced current in the present or absence of artemin. Figure shows averaged data fitted with the Hill equation (see methods). EC50 = 343 μM and Maximum current density = -64.4 pA/pF in the absence of artemin, EC50 = 396 μM and Maximum current density = -19.8 pA/pF in the presence of artemin. Data for each point were generated from separate neurons by application of AITC for 1 min after pretreatment of artemin or vehicle. Holding potential (Vh) = -60 mV in all experiments.