Antinociceptive action of Azadirachta indica (neem) in mice: possible mechanisms involved.

ABSTRACT

Azadirachta indica (AI, Neem) was tested for analgesic potency in experimental pain models in mice. In the glacial acetic acid (GAA) induced writhing test, AI (10, 30 and 100 mg/kg) dose-dependently reduced both the incidence and the number of writhes. Similarly, AI, at the dose levels tested, also enhanced tail withdrawal latencies in the tail-flick test for nociception. In the interaction studies, pretreatment with the opioid antagonist, naloxone (1 mg/kg) and the central noradrenaline depleter, DSP-4 (50 mg/kg) attenuated AI analgesia by differential degrees in both experimental models, whereas, the serotonin synthesis inhibitor, PCPA (300 mg/kg) potentiated the same. These results suggest that both central and peripheral mechanisms and complex neural pathways, opioid and non-opioid, may be involved in AI induced analgesia.