TrpA1 in larval brain BLA neurons is required for heat allodynia. (A and B) Behavioral responses to a 40 °C heat probe of larvae in which UAS-TrpA1-RNAi was expressed in various tissues under control of different GAL4 drivers. A copy of UAS-Dcr2 was included to increase RNAi efficiency. Behavioral assay was performed 24 h after UVC treatment. The sample numbers are indicated with brackets in A. Log-rank tests, corrected by total comparing group numbers, were performed to compare dataset displayed in accumulated response curves in A. Results of statistical analysis are marked in the bar graphs in B for clarity, and columns with different superscripts (a, b, and c) are significantly different from each other (P < 0.05). (C) Diagram of the cis-regulatory element R21G01 (black bar), located at the TrpA1 intron between exons 7 and 8. Arrows indicate alternative exons. (D) Expression of TrpA1-C, TrpA1-D, and R21G01 in larval CNS in transheterozygotes bearing TrpA1-(C or -D)-KI-T2A-lexA > lexAop2-6XmCherry and R21G01-GAL4 > UAS-6XGFP. BLA, BLP, VLT, and CC cells, are indicated by arrows. Enlarged view of a brain lobe is shown in the right-most panels. (E) R78E05 and R21G01 expression in larval CNS in transheterozygotes bearing R78E05-GAL4 > UAS-6XGFP and R21G01-lexA > lexAop2-6XmCherry. (F) R74A06 and TrpA1 expression in larval ventral nerve cord in transheterozygotes bearing R74A06-GAL4 > UAS-6XGFP and TrpA1-T2A-lexA > lexAop2-6XmCherry. (Scale bars in D–F, 100 μm.)