Striatal dopamine release and motivated behavior

这个项目的目的是确定纹状体多巴胺释放在动力和强化中的作用。最近，我们发现对大鼠乳头上核的化学刺激正在加强，这表明乳头上核可能是初级强化的一个组成部分。由于腹侧纹状体的多巴胺释放与初级强化有关，我们研究了电刺激乳头上核是否增强了腹侧纹状体的多巴胺释放，如伏安信号所示。大鼠学会了杠杆按压，在乳头上核传递短暂的电刺激序列，电流约为200微安。支持乳头上区域强烈自我刺激的电刺激序列诱导多巴胺释放，如伏安信号所示。乳头上刺激诱发的多巴胺信号与腹侧被盖刺激诱发的多巴胺信号的时间模式基本相同。这些结果表明，乳头上核刺激在腹侧纹状体触发多巴胺的释放，这与初级强化有关，乳头上核是与中脑边缘多巴胺系统相关的奖赏回路的一部分。

The aim of this project is to determine the role of striatal dopamine release in motivation and reinforcement. Recently, we found that chemical stimulation of the supramammillary nucleus is reinforcing in rats, suggesting that the supramammillary nucleus may be a component of primary reinforcement. Since dopamine release in the ventral striatum has been implicated in primary reinforcement, we examined whether electrical stimulation of supramammillary nucleus is reinforcing and evokes dopamine release in the ventral striatum as shown by voltammetric signals. Rats learned to lever-press to deliver brief trains of electrical stimulation at the supramammillary nucleus with currents around 200 micro A. Electrical trains that support vigorous self-stimulation at the supramammillary area induced dopamine released as indicated by voltammetric signals. Temporal patterns of dopamine signals evoked by supramammillary stimulation are essentially identical to those of evoked by ventral tegmental stimulation. These results suggest that supramammillary stimulation triggers dopamine release in the ventral striatum, which has been implicated in primary reinforcement, and that the supramammillary nucleus is part of the reward circuitry associated with the meso-limbic dopamine system.