RESUMO
Objective To investigate the influence on the behavior of withdrawal and relapse after deep brain stimulation of bilateral nucleus accumbens in morphine-dependent rats. Methods The rats with a strong unconditioned preference were discarded in preconditioning test, the selected rats were distributed into five groups randomly. After operation,morphine hydrochloride was injected subcutaneously into SD rats for 12 days (once every day,initial 5 mg/kg,increasing by 5 mg/kg per time,stable in 20 mg/kg ). A modified electrical circuit was used to procedure the DBS,the parameter was 130 Hz,150 A,60 s,l h/d,14 d. CPP test was used to exam the effect of DBS. A minor morphine dose (3 mg/kg) was injected to induce the behavior of relapse, and CPP was tested again after 24 h. Two-way ANOVA was performed on the data with Bonferroni posttest. Result ①After CPP training,CPP score of group morphine, morphine + sham and morphine + DBS was ( 155. 87 ± 20. 45 ) s, (107.33 ± 18.10)s,(135.45 ±22.09)s,and had significant difference with group of control( ( -70.34 ± 15.40) s)(t = 9.45,P＜0.01; t = 6.94,P＜0.01;t = 8.04,P＜0.01).②After 7 days' DBS,the CPP score in group of morphine + DBS reduced significantly compared to group of morphine( t = 4.21, P＜0.01) and morphine + sham( t=1.10, P＜0.05).0n the 14th day,there was more pronounced reduction ( t = 5. 15, P＜0.01; t = 3.92, P＜ 0.01). ③ 24 hours after the minor morphine dose was injected,the CPP score in morphine + DBS didn't increase significantly, and had significant difference with group of morphine ( t = 4.04, P＜0.01) and morphine + sham ( t= 4. 13, P＜0.01). Conclusion DBS bilateral nucleus accumbens in morphine-dependent rats can interfere the behavior of morphine-induced CPP and relapse.
