Dopaminergic enhancement of local food-seeking is under global homeostatic control.
Dopaminergic enhancement of local food-seeking is under global homeostatic control.
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DOI：
10.1111/j.1460-9568.2011.07916.x
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发表时间：
2012-01
期刊：
影响因子：
--
通讯作者：
Zhuang X
中科院分区：
文献类型：
--
作者：
Beeler JA;Frazier CR;Zhuang X
最近的研究表明，过量饮食和肥胖与多巴胺能机制有关，一些研究人员提出，与成瘾相关的多巴胺失调与肥胖的类似失调之间存在相似之处。然而，多巴胺在调节奖赏和强化中的确切作用仍然存在争议。与滥用药物不同，对自然回报的追求，如食物，受到动态平衡过程的调节，该过程假定保持稳定的能量平衡，使不受限制的消费和对回报的追求得到控制。理解奖励系统是如何受到或逃避自我平衡调节的是一个关键问题。在行为模式中广泛使用食物限制来激励动物受试者，这排除了对这种关系的研究，因为体内平衡系统被锁定在赤字模式中。在目前的研究中，我们研究了多巴胺在调节半自然主义家庭笼子范例中的适应性摄食行为中的作用，在这些范例中，小鼠所有的食物都是通过杠杆挤压获得的。我们在两个范例中比较了高多巴胺能多巴胺转运体缺陷小鼠(DATkd)和野生型小鼠(WT)的消费和进餐模式，这两个范例导致了采购食物的成本上升。我们发现，高多巴胺能小鼠表现出类似的需求弹性、体重减轻和能量平衡，以响应成本。然而，DATkd在进餐模式上表现出明显的差异。与增强动机的预期一致，多巴胺的增加增加了餐量，降低了餐内成本敏感度。尽管如此，这并没有改变整体的能源平衡。我们的结论是，多巴胺的增加增强了在就餐期间在当地工作的动机或意愿，而不会改变能量平衡，增强全球对食物的寻求或产生能量盈余。
Recent work has implicated dopaminergic mechanisms in overeating and obesity with some researchers suggesting parallels between the dopamine dysregulation associated with addiction and an analogous dysregulation in obesity. The precise role of dopamine in mediating reward and reinforcement, however, remains controversial. In contrast to drugs of abuse, pursuit of a natural reward, such as food, is regulated by homeostatic processes that putatively maintain a stable energy balance keeping unrestrained consumption and reward pursuit in check. Understanding how the reward system is constrained by or escapes homeostatic regulation is a critical question. The widespread use of food restriction to motivate animal subjects in behavior paradigms precludes investigation of this relationship as the homeostatic system is locked into deficit mode. In the present study, we examine the role of dopamine in modulating adaptive feeding behavior in semi-naturalistic home cage paradigms where mice earn all their food from lever pressing. We compared consumption and meal patterning between hyperdopaminergic dopamine transporter knock-down mice (DATkd) with wild-type (WT) in two paradigms that introduce escalating costs for procuring food. We found that hyperdopaminergic mice exhibited similar demand elasticity, weight loss and energy balance in response to cost. However, the DATkd show clear differences in meal patterning. Consistent with expectations of enhanced motivation, elevated dopamine increased meal size and reduced intrameal cost sensitivity. Nonetheless, this did not alter overall energy balance. We conclude that elevated dopamine enhances incentive or willingness to work locally within meals without shifting energy balance, enhancing global food-seeking or generating an energy surplus.
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影响因子：
16.2
作者：
Cagniard, Barbara;Beeler, Jeff A.;Zhuang, Xiaoxi
通讯作者：
Zhuang, Xiaoxi
影响因子：
10.9
作者：
Dallman, Mary F.
通讯作者：
Dallman, Mary F.
影响因子：
3.6
作者：
Figlewicz, Dianne P.;Sipols, Alfred J.
通讯作者：
Sipols, Alfred J.
影响因子：
5.4
作者：
Chaney, Melissa A.;Rowland, Neil E.
通讯作者：
Rowland, Neil E.
影响因子：
3.3
作者：
Cousins, MS;Trevitt, J;Salamone, JD
通讯作者：
Salamone, JD