A and B. Both AITC (100 μM) and carvacrol (50 μM) caused a significant increase in GLP-1 secretion from murine ileal cultures and were fully inhibited by the TRPA1 inhibitor HC-030031 (50 μM). C. Incubation of carvacrol (Car; 50 μM) in the presence of a complete voltage-gated ion channel block had no effect on GLP-1 secretion from murine ileal cultures, however, a significant increase in GLP-1 secretion was observed following a similar incubation with bombesin (Bom; 100 nM) (n=5-6, */#p<0.05, unpaired Student’s t-test). D-F. The polyunsaturated fatty acids AA, EPA and DHA (all at 200 μM), all caused robust and significant increases in GLP-1 secretion and were not affected by co-incubation with HC-030031 (50 μM). G and H. The effect of AITC and carvacrol to increase GLP-1 secretion from murine ileal cultures was abolished in trpa1−/− mice (black bars) compared to WT (white bars). Experiments were n=≥6 wells from ≥3 mice, unless otherwise indicated, */#p<0.05, **/##p<0.01, ***/###p<0.001, one-way ANOVA with Bonferroni post hoc test; * indicates significance level from baseline and # indicates significance level between groups. The dotted line on each graph represents the respective baseline value.