Activation of primary afferent neurons by 8,9-EET. (A) 8,9-EET induces direct calcium influx in sensory neurons. Calcium concentrations were monitored by ratiometric imaging using fura-2 in cultivated neurons from DRGs of adult wild- type mice. Shown is a representative trace. 40 mM KCL solution was used to identify all viable neurons (B). Average values of peak normalized to baseline ratios of experiments shown in panel B. Data shown represent the mean ± SEM from 12 experiments. Student's t test: *, p ≤ 0.05. (C) Phenotypic characterisation of 8,9-EET responsive neurons. Cultivated DRG neurons were stimulated with 10 μM 8,9-EET, 200 μM menthol, 300 nM capsaicin, 100 μM AITC and 40 mM KCL for 10 sec. Representative traces are shown. Relative amount of cells grouped according to their responsiveness to 8,9-EET and TRP-agonists. Percent values were calculated from 280 KCl responsive neurons. Values below the dotted line are the percentage of all 8,9-EET responding cells.