Study on analgesic effects of aqueous extract from Asari Radix et Rhizoma combined with Nimodipine and its mechanism / 中草药

ABSTRACT

Objective: To study the analgesic effects of aqueous extract from Asari Radix et Rhizoma (ARR) combined with Nimodipine and its mechanism. Methods: Forty healthy male Wistar rats were r andomly divided into control, model, ARR, Nimodipine, and ARR+Nimodipine groups. Except the control group, the neuropathic pain models of rats were produced in the rest groups by the ligation of sciatic nerve. Rats in each group were ig administered for two weeks after operation. The aqueous extract (200 mg/kg) from ARR was given to rats in ARR group, Nimodipine (40 mg/kg) was given to rats in Nimodipine group, and the aqueous extract (200 mg/kg) from ARR was given to rats after 30 min administration of Nimodipine (40 mg/kg) in ARR+Nimodipine group, and physiological saline was given to rats in the control and model groups. Thermal paw withdrawal latency and mechanical paw withdrawal reflex threshold of rats in each group were measured on one day before operation and on the days 1, 3, 5, 9, and 14 after 30 min of administration. Results: The thermal paw withdrawal latency and mechanical paw withdrawal reflex threshold of rats in each group were not significantly different before and after the operation (P>0.05). The thermal paw withdrawal latency and mechanical paw withdrawal reflex threshold of rats in the model group were significantly lower than those in the control group at various time points after the operation (P<0.05 and 0.01). The thermal paw withdrawal latency and mechanical paw withdrawal reflex threshold of rats in ARR and Nimodipine groups were significantly higher than those in the model group from the day 5 after the operation (P<0.05 and 0.01). The thermal paw withdrawal latency and mechanical paw withdrawal reflex threshold of rats in ARR+Nimodipine group were significantly higher than those in the model group from the day 3 after the operation (P<0.05 and 0.01), and were significantly higher than those of both in ARR and Nimodipine groups from the day 5 after the operation (P<0.05 and 0.01). Analgesic effects of ARR+Nimodipine group were better than those of separate ARR and Nimodipine groups. Conclusion: The aqueous extract from ARR combined with Nimodipine has the ideal analgesic effects.