Mechanism of Antinociceptive Effect of Vanillin in Formalin Test

Vanillin is the active component of Vanillus planifolia seeds and is widely used as a flavoring agent in food and pharmaceutical industries. It has shown anti-inflammatory and antinociceptive properties. The aim of the present research was to investigate its possible mechanism(s) in formalin test.

Male Swiss mice (25-30 g) were used. Formalin test was used to evaluate the antinociceptive effect. Different groups of mice were pretreated with prazocin (2 mg/kg), yohimbine (5 mg/kg), propranolol (2 mg/kg), cyproheptadine (2 mg/kg), ondansetron (2 mg/kg), naloxone (5 mg/kg), sulpiride (20 mg/kg), arginine (100 mg/kg), L-NAME (20 mg/kg), methylene blue (5 mg/kg), or glibenclamide (10 mg/kg) to evaluate the role of pertinent receptors or pathways on vanillin-induced antinociception.

Vanillin showed antinociceptive effect in the second phase of formalin test. Pretreatment with ondansetron, sulpiride, L-NAME, methylene blue, or glibenclamide prevented vanillin antinociceptive effect.

Vanillin showed antinociceptive effect in formalin test, and according to the results, the NO/cGMP/K_ATP pathway and serotonin 5HT₃ and dopamine D₂ receptors have an important contribution to its antinociceptive effect, but opioid and adrenergic receptors are not involved in this effect.