Effect of electro-acupuncture on relapse to heroin-seeking in the heroin self-administrating rats

Abstract

To observe the effect of electro-acupuncture on the relapse to heroin-seeking induced by heroin-related cues after withdrawal from heroin self-administration in rats. Sixty male Wistar rats were randomized into physiological saline group, withdrawal group A, withdrawal group B, electro-acupuncture (EA) treatment group A and EA treatment group B, with 12 rats in each group. The rats were trained by nose-poke response to self administer heroin (50 μg/kg/per infusion) or saline with one daily 4-h session for 14 consecutive days, the session ended after 25 infusions were earned or 4 hours had passed, the reinforcement schedule was a progressive ratio. Then rats in withdrawal group A and withdrawal group B were withdrawn from heroin for 1 week and 2 weeks respectively, and then they were reintroduced to their training chambers for 4-h relapse testing which was induced by heroin-related environmental cues; And rats in EA treatment group A and EA treatment group B were also withdrawn from heroin for 1 week and 2 weeks respectively, during which they were given EA treatment for 20 min daily, then they received relapse testing; In the meantime, rats in saline group were trained with saline instead of heroin for 14 days as control, after 7 days of withdrawal from saline, they received relapse testing. Following 7–8 days of drug training, the rats began to establish the stable intravenous heroin self-administration behavior; For the stable heroin self-administrating rats that received EA treatment, when they were reintroduced to their training chambers, their heroin-seeking behaviors were obviously inhibited, and this inhibitory effect related to the cumulativeness of EA stimulation. The results suggested that EA could prevent relapse to heroin-seeking to a certain extent.