Interaction of the effect of histaminergic system and aqueous extract of Barberry on formalin-induced pain in male rats

Barberry fruit (Berberis vulgaris L.) has been introduced in Iranian traditional medicine as a pain reliever. The aim of this study was to investigate the interaction of the histaminergic system and aqueous extract of Barberry on formalin-induced pain in rats. In this experimental study, 48 male Wistar rats weighing 220-250 g, were divided into in 8 groups with 6 rats in each groups: control group (normal saline + 1% formalin intraplantar injection), 3 treatment group with aqueous extract of barberry (75, 150 and 300 mg/kg), treatment group with pyrilamine, H1 receptor antagonist (10 mg/kg) alone, pretreatment group with pyrilamine (10 mg/kg) + aqueous extract of barberry (300 mg/kg), Treatment group with famotidine, H2 receptor antagonist (20 mg/kg) alone, pretreatment group with famotidine (20 mg/kg) + aqueous extract of barberry (300 mg/kg). Pain was evaluated by formalin test. Data analysis was performed using one-way ANOVA and then Duncan's test. Intraperitoneal injection of aqueous extract of barberry significantly reduced the pain response in the second phase of formalin pain (p <0.05). Pre-treatment of pyrilamin and famotidine and then aqueous extract of barberry improved the analgesic response of the aqueous extract of barberry in the second phase of formalin pain (p <0.05). The results of this study indicated that the aqueous extract of barberry may have analgesic effects by potentiating the pain relief potentials by histamine antagonists, especially the H1 receptor antagonist.