Putting desire on a budget: dopamine and energy expenditure, reconciling reward and resources.
Putting desire on a budget: dopamine and energy expenditure, reconciling reward and resources.
复制标题
DOI：
10.3389/fnint.2012.00049
复制
发表时间：
2012
影响因子：
3.5
通讯作者：
Zhuang X
中科院分区：
文献类型：
--
作者：
Beeler JA;Frazier CR;Zhuang X
越来越多的证据表明，多巴胺的功能与代谢信号的整合，突显了多巴胺在能量平衡中的潜在作用，通常被解释为调节对体内平衡状态的奖赏。尽管多巴胺的确切作用仍然存在争议，但它的奖赏观点主导了包括肥胖在内的动机障碍的研究。在这里概述的假说中，我们认为多巴胺在行为中的主要作用是调节活动，使行为能量消耗适应普遍的环境能量条件，而多巴胺在奖励和动机行为中的作用源于它在能量平衡中的主要作用。长期以来，人们一直知道多巴胺可以调节活动，通过多巴胺发挥作用的精神刺激剂就是一个例子。最近，关于多巴胺在调节自愿活动中的作用的研究刚刚起步，一些研究人员认为，多巴胺可能是将能量感知与调节的自愿能量消耗结合起来的最终共同途径。我们认为，在来自内部和外部世界的输入之间，多巴胺沿着两个轴调节行为能量消耗：一个是调节一般活动的保存-支出轴，另一个是调节奖励价值偏向活动分布程度的探索-开发轴。在这种观点下，增加多巴胺并不能促进美味食物的消费。相反，多巴胺的增加促进了能源消耗和勘探，而减少的多巴胺有利于能源的节约和开发。这一假说为一个明显的悖论提供了一种机械解释：多巴胺在寻找食物方面的作用已经得到证实，以及低多巴胺能功能与肥胖相关的发现。我们的假说为多巴胺在肥胖中的作用提供了另一种视角，并将“奖赏缺乏假说”重新解释为可感知的能量缺乏。我们建议，多巴胺，通过促进能量消耗，应该对肥胖具有保护作用。我们认为，在肥胖率高的西方社会，这种保护机制的明显失败是由于久坐不动的生活方式阻碍了能量消耗。
Accumulating evidence indicates integration of dopamine function with metabolic signals, highlighting a potential role for dopamine in energy balance, frequently construed as modulating reward in response to homeostatic state. Though its precise role remains controversial, the reward perspective of dopamine has dominated investigation of motivational disorders, including obesity. In the hypothesis outlined here, we suggest instead that the primary role of dopamine in behavior is to modulate activity to adapt behavioral energy expenditure to the prevailing environmental energy conditions, with the role of dopamine in reward and motivated behaviors derived from its primary role in energy balance. Dopamine has long been known to modulate activity, exemplified by psychostimulants that act via dopamine. More recently, there has been nascent investigation into the role of dopamine in modulating voluntary activity, with some investigators suggesting that dopamine may serve as a final common pathway that couples energy sensing to regulated voluntary energy expenditure. We suggest that interposed between input from both the internal and external world, dopamine modulates behavioral energy expenditure along two axes: a conserve-expend axis that regulates generalized activity and an explore-exploit axes that regulates the degree to which reward value biases the distribution of activity. In this view, increased dopamine does not promote consumption of tasty food. Instead increased dopamine promotes energy expenditure and exploration while decreased dopamine favors energy conservation and exploitation. This hypothesis provides a mechanistic interpretation to an apparent paradox: the well-established role of dopamine in food seeking and the findings that low dopaminergic functions are associated with obesity. Our hypothesis provides an alternative perspective on the role of dopamine in obesity and reinterprets the “reward deficiency hypothesis” as a perceived energy deficit. We propose that dopamine, by facilitating energy expenditure, should be protective against obesity. We suggest the apparent failure of this protective mechanism in Western societies with high prevalence of obesity arises as a consequence of sedentary lifestyles that thwart energy expenditure.