Sorg B A, Kalivas P W
Department of Veterinary and Comparative Anatomy, Washington State University, Pullman 99164-6520.
Brain Res. 1991 Sep 13;559(1):29-36. doi: 10.1016/0006-8993(91)90283-2.
Behavioral and neurochemical cross-sensitization between cocaine and stress was examined. The effects of stress and cocaine on extracellular levels of dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were measured by in vivo microdialysis in the rostral ventral striatum, including the nucleus accumbens. Pretreatment with a daily 20 min footshock stress (0.45 mA/200 ms/s) for 5 days enhanced the cocaine-induced increase in extracellular dopamine levels in shock compared to sham shock-pretreated rats. The motor stimulant response to acute cocaine was also augmented in shock-pretreated rats. There was a slight but significant decrease in the levels of DOPAC and HVA in both groups following cocaine but no differences between shock and sham shock animals. In contrast, in the converse experiment, pretreatment with daily cocaine (15 mg/kg, i.p.) for 5 days did not significantly alter the stress-induced levels of extracellular dopamine compared to controls. The levels of DOPAC and HVA were not different between cocaine- and saline-pretreated groups although there was a trend towards enhanced metabolite levels in cocaine-pretreated animals. These data in part support a role for enhanced dopamine neutrotransmission in mediating behavioral cross-sensitization between psychostimulants and stress.
研究了可卡因与应激之间的行为和神经化学交叉致敏作用。通过在包括伏隔核在内的吻侧腹侧纹状体中进行体内微透析，测量了应激和可卡因对多巴胺及其代谢产物3,4-二羟基苯乙酸（DOPAC）和高香草酸（HVA）细胞外水平的影响。与假电击预处理的大鼠相比，每天进行20分钟足部电击应激（0.45 mA/200 ms/s）预处理5天，增强了可卡因诱导的电击大鼠细胞外多巴胺水平的升高。电击预处理的大鼠对急性可卡因的运动兴奋反应也增强。两组在给予可卡因后DOPAC和HVA水平均有轻微但显著的下降，但电击组和假电击组动物之间无差异。相反，在反向实验中，与对照组相比，每天给予可卡因（15 mg/kg，腹腔注射）预处理5天并未显著改变应激诱导的细胞外多巴胺水平。可卡因预处理组和生理盐水预处理组的DOPAC和HVA水平没有差异，尽管可卡因预处理动物的代谢产物水平有升高的趋势。这些数据部分支持了多巴胺神经传递增强在介导精神兴奋剂与应激之间的行为交叉致敏中所起的作用。
