The Involvement of Non Opioidergic Mechanism in the Antinociceptive and Antilocomotive Activity of Bacopa monnieri

A hydroethanolic extract (HE-ext) of Bacopa monnieri (BM) was studied for antinociceptive effect in the animal models of acetic-acid-induced writhing test and antilocomotive effect in mice. Standard centrallyacting analgesic, morphine (MP), and peripherally-acting one, diclofenac (Diclo), were also tested along with the extract for comparison. The extract exhibited significant antinociceptive effect (p < 0.001) in this test, not antagonized by the opioid receptor antagonist, naloxone (NLX) in a fashion similar to diclofenac. This excluded the involvement of opioids in the mediation of antinociceptive response of Bacopa monnieri. Moreover, the BM HE-ext exhibited highly significant antilocomotive (p < 0.0001) that was also unaffected by naloxone. These results indicate that Bacopa monnieri possesses antinociceptive and antilocomotive effect that may be mediated through non-opioidergic mechanism.