The effects of restraint stress and sensitization on the behavioral and neuronal responses to methamphetamine

• Main Authors: Shu-ting Chen, 陳淑婷
• Other Authors: Chung-Chih Kuo
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/87321885456256220983

碩士 === 慈濟大學 === 生理暨解剖醫學碩士班 === 100 === Methamphetamine (MA) is one of the popular abused drugs. MA induces rewarding effect and dependence. In rodents, MA administration also induces the increase of locomotor activity. Repeated exposure to MA induces behavioral sensitization, which the increase of locomotor activity induced by MA challenge is enhanced. MA blocks the dopamine transporters and enhances the dopamine levels in the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc). In addition, stress results in the drug craving and relapse. That restrain stress induces behavioral sensitization to stimulating and reinforcing properties of abuse drugs. However the mechanism of stress enhancing the effect of MA is still not clear. The aim of this study is to investigate the neuronal responses of mPFC and NAc to MA and effect of restraint stress and sensitization on this response. The recording electrodes were implanted in mPFC and NAc chronically. The neuronal activities of mPFC and NAc were recorded during MA challenges. Restraint stress was applied before MA challenge. The rats were sensitized to MA with repeated administration of MA and the effect of restraint stress on the MA challenge was examined again. The results showed that restraint stress increased the behavioral response to MA and this effect was enhanced after MA sensitization. MA challenge increased the firing rates of some units recorded in mPFC and NAc. The restraint stress enhanced the neuronal response to MA challenge and this enhancement was enlarged after MA sensitization. Our results suggested that stress raised the effect of abused drug and mPFC and NAc was involved in the effect of restraint stress and MA sensitization.