Short-chain lipids do not activate TRPV1. All representative traces were obtained at −120 and +120 mV. A, initial (in the absence of agonist, gray), after 5 min of 5 μm LPA 6:0 (red), and after 4 μm capsaicin (Caps, black). B, initial currents are in gray, after 5 μm FAP-15 (red), and after 4 μm capsaicin (Caps, black). C, initial currents are in gray, after 5 min of 5 μm of FAP-17 (red), and after 4 μm capsaicin (Caps, black). D, initial currents (gray) in the presence of a concentration of 5 μm monounsaturated FAP-14 for 5 min (red) and after 4 μm capsaicin (Caps, black). E, horizontal line within each box indicates the median; boxes show the 25th and 75th percentiles, and whiskers show the 5th and 95th percentiles of the data obtained at +120 mV and normalized to activation by 4 μm capsaicin. Data for all short-chain LPA molecules synthesized are depicted (n = 5 for LPA 6:0; 6 for FAP-15, FAP-16, FAP-17, and FAP-14). F, overlay assay for LPA 6:0 and FAP-15, -16, -17, and -14. FAP-14 clearly interacts with TRPV1, whereas fainter signals (or the lack of them) are observed for LPA 6:0 and FAP-15–17. The negative control was LPA 18:0 and the positive control was LPA 18:1. G, densitometry was performed for the different lipid spots and normalized with respect to the positive control (LPA 18:1). Data are shown as in E (n = 2).