Deep brain stimulation of bilateral nucleus accumbens at high frequency inhibits addiction behavior extinction in rats

Abstract

Objective To investigate the influence of deep brain stimulation (DBS) at high frequency to the bilateral nucleus accumbens on morphine-induced conditioned place preference (CPP) and relapse behaviors during extinction phase in rats. Methods Twenty adult SD rats were employed in the experiment. Through stereotactic operation, outer electrode cannula was implanted into rats′ bilateral nucleus accumbens. After 5 days of rest, the morphine-dependent rat model with CPP was established through intraperitoneal morphine injection (10 mg/kg). The rats, after being randomly divided into experimental group (morphine+ DBS) and control group (morphine+ sham DBS), were electrically stimulated using DBS circuits. Rats in the experimental group were given high frequency electrical stimulations while the control group was given sham stimulation. The CPP score of the two groups was recorded the day after stimulation until successful extinction and then the extinction time was compared between the two groups. After successful extinction the rats were given small dose of morphine to trigger relapse within 24 hours, and the CPP score was recorded and compared between the two groups. Results Compared with the control group (six days), the experimental group (26 days) had a longer extinction time. After relapse, the retention time within the drug-paired chamber of the experimental group was (357.01±192.72) s, obviously shorter than that of the control group ((704.91±181.35) s; t=2.370, P=0.034 6). Conclusion High frequency DBS to rats′ bilateral nucleus accumbens can prolong extinction time but inhibit relapse behavior. Key words: Electric stimulation therapy; Nucleus accumbens; Morphine; Behavior, addictive; Recurrence