Fig. 9.

Exendin-4 (Ex-4)-induced substance P (SP) release does not occur in sensory neurons from transient receptor potential ankyrin 1 (TRPA1)/transient receptor potential vanilloid 1 (TRPV1) double knockout (KO) dorsal root ganglia (DRG). Mouse primary cultured DRG neurons (black bars) from TRPA1/TRPV1 double KO animals were cocultured with SP sensors (gray bars) and exposed to 50 nM Ex-4, followed by capsaicin (Cap), allyl isothiocyanate (AITC), and KCl. Concentrations of the treatments were as described in Fig. 6. Greater than 400 neurons were examined in 3 independent cultures from 4 mice. Bars are means ± SE (n = 4 animals). NFR, normalized fura-2 AM response; NS, not significant. Statistical analysis was by ANOVA using Tukey's post hoc test.