Hernandez Giovanni, Hamdani Selma, Rajabi Heshmat, Conover Kent, Stewart Jane, Arvanitogiannis Andreas, Shizgal Peter
Center for Studies in Behavioural Neurobiology, Concordia University, Montreal, PQ, Canada.
Behav Neurosci. 2006 Aug;120(4):888-904. doi: 10.1037/0735-7044.120.4.888.
Extracellular dopamine levels were measured in the rat nucleus accumbens by means of in vivo microdialysis. Delivery of rewarding medial forebrain bundle stimulation at a low rate (5 trains/min) produced a sustained elevation of dopamine levels, regardless of whether train onset was predictable. When the rate of train delivery was increased to 40 trains/min, dopamine levels rose rapidly during the first 40 min but then declined toward the baseline range. The rewarding impact of the stimulation was reduced following prior delivery of stimulation at the high, but not the low, rate. These results support the idea that dopamine tone plays an enabling role in brain stimulation reward and is elevated similarly by predictable and unpredictable stimulation.
通过体内微透析法测量大鼠伏隔核中的细胞外多巴胺水平。以低频率（5次/分钟）给予中脑边缘束的奖赏性刺激会使多巴胺水平持续升高，无论刺激开始是否可预测。当刺激频率增加到40次/分钟时，多巴胺水平在前40分钟内迅速上升，但随后降至基线范围。在以高频率而非低频率预先给予刺激后，刺激的奖赏作用减弱。这些结果支持了多巴胺张力在脑刺激奖赏中起促进作用的观点，并且可预测和不可预测的刺激都会使其同样升高。
