FANG Jun, GU Jian-wen, YANG Wen-tao, QIN Xue-ying , HU Yong-hua

Background  Stereotactic surgery has been used to treat heroin abstinence in China since 2000 by ablating the amygdaloid nucleus (AMY) and the nucleus accumbens (NAc), which also provides opportunity to identify the relationship between these nuclei and addiction. Our study aimed to explore the physiological and psychological effects of electrically stimulating the AMY and the NAc in heroin addicts after detoxification by observing changes of heart rate, arterial pressure and occurrence of euphoria similar to heroin induced euphoria.
Methods  A total of 70 heroin addicts after detoxification were recruited, and 61 of them were eligible to be given stereotactic surgery for heroin abstinence. The operation was carried out after determining the coordinates of all target nucleuses, and stimulation was performed at the AMY and the NAc solely or jointly. Heart rate, arterial pressure and occurrence of euphoria similar to heroin induced euphoria were recorded and analyzed.
Results  The average heat rate was (66±10) beats/min before electric stimulation, and significantly increased to (84±14) beats/min during stimulation, and changed to (73±12) beats/min 10 minutes after stimulation. There was a significant elevation of the average arterial pressure from 83 mmHg before stimulation to 98 mmHg during the stimulation, and it then decreased to 90 mmHg after stimulation. Forty-three of the 61 patients showed intense euphoria similar to heroin induced euphoria. The largest number (118/186) of euphoric responses occurred when the AMY and the NAc were stimulated at the same time. Odds ratio was 5.4 (95% CI: 2.4–11.9, P <0.0001) to quantify the association. Results from a Logistic regression model showed a positive correlation between unilateral stimulation of either the AMY or NAC and induction of euphoria (OR >1), especially when the left AMY or left NAc was stimulated (P <0.05).
Conclusions  Our data are consistent with existing results that the AMY and the NAc are related to addiction. Different roles in drug dependence would be suggested according to the location of the AMY and NAc.