Role of transient receptor potential vanilloid type 1 in the trigeminal ganglion and brain stem following dental pulp inflammation

Aim To verify whether experimentally induced pulpitis activates the expression of transient receptor potential vanilloid type 1 (TRPV1) and c‐Fos, both peripherally and centrally. Methodology Acute pulpitis was induced in Sprague‐Dawley rats via pulp exposure and application of complete Freund's adjuvant (CFA; n = 13). Saline‐treated (n = 13) rats and rats that did not undergo tooth preparation (n = 13) served as control groups. Three days post‐CFA or post‐saline application, face grooming activity was recorded, and the rats were then euthanized to allow for immunohistochemical analysis of the trigeminal ganglion (TG) and spinal trigeminal nucleus. anova with Student's t‐test for post‐hoc analysis was used to quantify the differences in behavioural tests and immunohistochemical labelling (c‐Fos and TRPV1) in TG amongst groups. Kruskal–Wallis test with Dunnett's test for post‐hoc analysis was used to compare immunohistochemical labelling (c‐Fos and TRPV1) in the brainstem amongst groups. Results Histological evidence of severe pulp inflammation was found, and there was a significant increase in pain‐like behaviour (P