Activation of Dopamine Receptors in the Nucleus Accumbens Promotes Sucrose-Reinforced Cued Approach Behavior
Activation of Dopamine Receptors in the Nucleus Accumbens Promotes Sucrose-Reinforced Cued Approach Behavior
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DOI：
10.3389/fnbeh.2016.00144
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发表时间：
2016-07-14
影响因子：
3
通讯作者：
Nicola, Saleem M.
中科院分区：
文献类型：
--
作者：
du Hoffmann, Johann;Nicola, Saleem M.
多巴胺受体激活在丘脑核（NAc）促进强烈的环境线索的食物寻求在饥饿的大鼠。然而，随意喂食的大鼠对食物预测线索的反应较少，特别是当食物奖励的价值较低时。在这里，我们调查这种差异是否可能是由于在NAc的多巴胺受体激活程度的差异。首先，我们观察到，尽管大鼠在其家中的笼子里随意获得食物接近食物容器，以响应奖励预测线索，但随着动物积累食物奖励，这种方法的数量下降。有趣的是，食物的线索方法发生在集群中，几个线索的反应，然后是连续的无反应。这种模式表明，行为是由两种状态之间的转换决定的，反应和非反应。注射D1或D2多巴胺受体激动剂到NAc剂量依赖性地增加线索响应，促进过渡到响应状态，并通过防止过渡到非响应状态。相反，D1或D2受体的拮抗剂通过诱导向无反应状态的转变和通过阻止向反应状态的转变来促进长时间的无反应发作。此外，在试验间隔期间的运动行为与反应状态相关，多巴胺受体激动剂也增加。这些结果表明，NAc多巴胺受体的激活起着重要的作用，在规范的饱腹感的条件下，调节接近食物的概率。
Dopamine receptor activation in the nucleus accumbens (NAc) promotes vigorous environmentally-cued food seeking in hungry rats. Rats fed ad libitum, however, respond to fewer food-predictive cues, particularly when the value of food reward is low. Here, we investigated whether this difference could be due to differences in the degree of dopamine receptor activation in the NAc. First, we observed that although rats given ad libitum access to chow in their home cages approached a food receptacle in response to reward-predictive cues, the number of such approaches declined as animals accumulated food rewards. Intriguingly, cued approach to food occurred in clusters, with several cued responses followed by successive non-responses. This pattern suggested that behavior was dictated by transitions between two states, responsive and non-responsive. Injection of D1 or D2 dopamine receptor agonists into the NAc dose-dependently increased cue responding by promoting transitions to the responsive state and by preventing transitions to the non responsive state. In contrast, antagonists of either D1 or D2 receptors promoted long bouts of non-responding by inducing transitions to the non-responsive state and by preventing transitions to the responsive state. Moreover, locomotor behavior during the inter-trial interval was correlated with the responsive state, and was also increased by dopamine receptor agonists. These results suggest that activation of NAc dopamine receptors plays an important role in regulating the probability of approach to food under conditions of normative satiety.