Selective elimination of isolectin B4-binding trigeminal neurons enhanced formalin-induced nocifensive behavior in the upper lip of rats and c-Fos expression in the trigeminal subnucleus caudalis

•We examined the role of IB4+ non-peptidergic C-fibers in orofacial pain.•The IB4-Sap treatment decreased IB4+ terminals in the Vc and IB4+ TG neurons.•The IB4-Sap treatment increased formalin-induced FRB and c-Fos-IR cells in the Vc.•Systemic bicuculline and muscimol had decreasing effects on FRB and c-Fos-IR cells.•IB4+ neurons play antinociceptive roles that are modulated by GABAA functions.