Fiorino D F, Coury A, Fibiger H C, Phillips A G
Department of Pyschology, University of British Columbia, Vancouver, Canada.
Behav Brain Res. 1993 Jun 30;55(2):131-41. doi: 10.1016/0166-4328(93)90109-4.
In vivo microdialysis with HPLC-ED was used to measure dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) in the nucleus accumbens of the rat, prior, during, and after 15-min periods of electrical brain stimulation at sites in the ventral tegmental area (VTA) that supported intracranial self-stimulation (ICSS). In the first experiment, both ICSS and yoked stimulation of the VTA evoked significant increases in extracellular concentrations of DA, its metabolites, and 5-HIAA. Comparable results from ICSS and yoked groups were interpreted as evidence that the rewarding properties of VTA stimulation were a causal factor in the elevated DA transmission in the nucleus accumbens, rather than intense operant behavior. Further evidence for this hypothesis came from a second set of data in which changes in extracellular DA levels during the measurement of rate/intensity functions for ICSS were positively correlated. 5-HIAA concentrations also increased during ICSS but these changes were not correlated with either ICSS rate or current intensity, suggesting that changes in serotonin metabolism were unlikely to subserve brain stimulation reward in the VTA. These results add to the growing body of evidence linking changes in extracellular DA in the mesolimbic DA system with both brain stimulation reward and the conditioned and unconditioned rewarding effects of biologically relevant stimuli.
采用高效液相色谱 - 电化学检测法（HPLC - ED）进行体内微透析，以测量大鼠伏隔核中多巴胺（DA）、3,4 - 二羟基苯乙酸（DOPAC）、高香草酸（HVA）和5 - 羟吲哚乙酸（5 - HIAA）的含量，测量时间为腹侧被盖区（VTA）支持颅内自我刺激（ICSS）的部位在进行15分钟脑电刺激之前、期间和之后。在第一个实验中，ICSS和VTA的配对刺激均引起DA及其代谢产物以及5 - HIAA细胞外浓度的显著增加。ICSS组和配对组的类似结果被解释为证据，表明VTA刺激的奖赏特性是伏隔核中DA传递升高的一个因果因素，而非强烈的操作性行为。该假设的进一步证据来自第二组数据，其中在测量ICSS的速率/强度函数期间细胞外DA水平的变化呈正相关。5 - HIAA浓度在ICSS期间也有所增加，但这些变化与ICSS速率或电流强度均无相关性，这表明血清素代谢的变化不太可能参与VTA中的脑刺激奖赏。这些结果进一步证明了中脑边缘DA系统中细胞外DA的变化与脑刺激奖赏以及生物相关刺激的条件性和非条件性奖赏效应之间的联系，相关证据日益增多。
