Figure 8.

Introduction of the mammalian TRPV1 channel to both painless and dTRPA1 populations confers aversion to capsaicin. To further examine the circuitry associated with aversion, we introduced the mammalian TrpV1 channel to either painless or dTRPA1-expressing cells and measured their response to capsaicin, a TrpV1 agonist. Expression of TrpV1 in either painless or dTRPA1 cells produced no change in PER frequencies in the presence of capsaicin (A), but TrpV1 introduction to both cell populations, did reduce the frequency of PER response to capsaicin. Similar results were obtained in food consumption (B), in which TrpV1 introduction to either cell population alone produced no aversion to capsaicin, but did once TrpV1 was added to both populations. Lastly, oviposition preference was unaltered in painless >TrpV1 or dTRPA1 >TrpV1 genotypes, but was significantly changed (P < 0.05 wilcoxon signed rank test) in TrpV1 introduction to both cell populations (C).