Wireless Telemetry Electrical Activity On Nucleus Accumbens Shell In Morphine-Induced CPP And Morphine-Induced Extinction Rats

Objective:To analyse the relationship between the electrical activity changes of nucleus accumbens(NAc) shell and the drug-seeking behavior by recording NAc shell electrical activity in morphine-induced conditioned place preference(CPP) and morphine-induced extinction rats.Methods: 40 rats were divided randomly into operation-only control group and the morphine-induced CPP group after stereotaxic electrode was buried on rats NAc shell and the latter group was made the morphine CPP model. A CPP video system combining with the technique of electrical activity wireless telemetry was used in the study. The NAc electrical activity from each group of rats was recorded by wireless telemetry respectively, which included staying in black or white chamber of video box, shuttling between black-white chambers and between white-black chambers. The electrical activity differences were analyzed by the percentage of each wave.Results: 1.When the morphine-induced rats staying in black chamber, compared with the operation-only control group, the NAc Shell electrical activity showed that the percentage of 0~10Hz was increased(P<0.05), meanwhile, those of 10~20Hz and 30~40Hz were reduced(P<0.05, P<0.01); when the morphine-induced rats staying in white chamber, the NAc Shell electrical activity showed that the percentage of 0~10Hz and 30~40Hz were increased(P<0.05,P<0.01), that of 10~20Hz was reduced(P<0.05,P<0.01); when the morphine-induced rats in black-white shuttling status, the NAc Shell electrical activity showed that the percentage of 0~10Hz was increased(P<0.05, P<0.01), that of 10~30Hz was reduced(P<0.05);and in the white-black shuttling status, the electrical activity showed that the percentage of 0~10Hz was reduced(P<0.05), that of 10~30Hz was increase(P<0.05); the electrical activity was further compared between staying status and shuttling status in the morphine-induced CPP group. There is no significant difference electrical activity between the rats in white-black shuttling status and staying in white chamber. However, when rats in black-white shuttling status, compared with staying in black chamber, the electrical activity showed that the percentage of 0~10Hz and 40~50Hz were increased(P<0.05), meanwhile, those of 10~20Hz and 30~40Hz were reduced(P<0.05). 2.When the morphine-induced extinction rats in black-white shuttling status, compared with the morphine-induced CPP rats, the NAc Shell electrical activity showed that the percentage of 0~10Hz was reduced(P<0.05), that of 20~30Hz was increased(P<0.05). When the morphine-induced extinction rats in white-black shuttling status, compared with the morphine-induced CPP rats, the NAc Shell electrical activity showed that the percentage of 0~10Hz was increased(P<0.05), that of 20~30Hz was reduced(P<0.05). When the morphine-induced extinction rats in white-black shuttling status, compared with staying in black chamber, the NAc Shell electrical activity showed that the percentage of 0~10Hz was reduced(P<0.05), that of 20~30Hz was increased(P<0.01). When the morphine-induced extinction rats in black-white shuttling status, compared with operation-only control group rats, the NAc Shell electrical activity showed that the percentage of low frequency beta wave was reduced(P<0.05,P<0.01), that of high frequency alpha wave had no significantly difference.Conclusion: 1. The electrical activity changes on NAc Shell in morphine-induced CPP rats was different from the operation-only control group, and these changes might be associated to the rat’s drug-seeking behavior. 2. When the morphine-induced extinction rats in black-white shuttling status, the NAc Shell electrical activtiy showed that the oscillation of δ~θwave was reduced, and that of high frequency beta wave was increased, these change was a further evidence of these electrical activity might be associated to the rat’s drug-seeking behavior. Meanwhile, in the extinction phase, the change of NAc Shell electrical activity, which was affected by the morphine-inducing, was became normal and has a trend of going back to the baseline, it might be associated to the extinction phase.