Objective: To observe the effect of electroacupuncture (EA) on the spatial learning-memory ability and the expression of NR 2 B subunit of NMDA receptor in the amygdala (AMG) in rats with morphine withdrawal.
Methods: A total of 40. SD rats were randomized into control, model, manual acupuncture and EA groups (n = 10 in each group). The morphine withdrawal model was established by subcutaneous injection of morphine hydrochloride injection at doses of 20, 30, 40, 50 and 50 mg . kg-1 . d-1 continuously for 5 days, followed by injection of naloxone (i. p., 3 mg/kg) for rapid induction of withdrawal syndrome. Manual acupuncture or EA stimulation was applied to bilateral "Shenshu"(BL 23) and "Zusanli" (ST 36), once daily for 6 days. Morris water maze swimming test was conducted for detecting the rats' spatial learning-memory ability. The expression levels of NR 2 B protein and mRNA in AMG was measured by Western blot and Real time-PCR, respectively.
Results: Compared to the control group, the escape latency on day 5 of swimming tests was obviously prolonged in the model group (P<0. 01), while in comparison with the model group, the escape latencies in both manual acupuncture and EA groups were obviously shortened (P<0. 01), suggesting an improvement of the rats' learning-memory ability. In addition, the expression levels of NR 2 B protein in both manual acupuncture and EA groups and that of NR 2 B mRNA in the EA group were significantly higher than those of the model group (P<0. 01, P<0. 05).
Conclusion: Both manual acupuncture and EA interventions can improve the learning-memory ability in morphine withdrawal rats, which is probably partially related to their effects in up-regulating the expression of NR 2 B in the AMG.