Involvement of dopamine and opioids in the motivation to eat: influence of palatability, homeostatic state, and behavioral paradigms
Involvement of dopamine and opioids in the motivation to eat: influence of palatability, homeostatic state, and behavioral paradigms
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DOI：
10.1007/s00213-008-1390-6
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发表时间：
2009-04-01
影响因子：
3.4
通讯作者：
Cador, Martine
中科院分区：
文献类型：
--
作者：
Barbano, M. Flavia;Le Saux, Maryvonne;Cador, Martine
食物的动机取决于几个变量，包括食物的适口性、有机体的稳态以及获得奖励所需的行为的性质。然而，迄今为止，很少有研究试图同时考虑所有这些变量来评估食物的动机。由于多巴胺和阿片类药物深深参与了喂养的调节，因此考虑所有提到的变量来研究它们的作用是很有意义的。在这项研究中，我们使用不同的行为范式评估了多巴胺和内源性阿片类药物对食物消耗和食物动机的参与，当考虑到食物适口性和稳态时，获得奖励的运动要求不同。不同的行为范式测量动机状态，但需要不同的运动输出（跑道和操作性渐进比率 3 任务）。当这些任务被学会并稳定时，进行纳洛酮或氟哌噻吨的外周注射。当颗粒可口时，纳洛酮会减少食物摄入量，而氟哌噻吨没有任何影响。当考虑动机时，纳洛酮会降低跑道测试和渐进比率测试中的表现，而氟哌噻吨仅在渐进比率测试中有效。损害阿片类神经传递会降低获取食物的动机，可能是通过降低食物奖励的可口性来实现的。多巴胺能系统似乎更多地参与以成本/收益相关的方式获取食物的动机的调节。
Motivation for food depends on several variables including food palatability, the homeostatic state of the organism, and the nature of the behavior required to obtain the reward. However, few studies to date have tried to evaluate motivation for food considering all these variables at the same time. Since dopamine and opioids have been deeply involved in the regulation of feeding, it is of interest to investigate their role considering all the mentioned variables.In this study, we evaluated the involvement of dopamine and endogenous opioids on food consumption and food motivation using behavioral paradigms that differ in the motor requirement to gain access to the reward, when food palatability and homeostatic state were taken into account.Pellets differentiated on palatability were offered to sated and restricted rats in consummatory tests and in different behavioral paradigms measuring motivational state, but requiring different motor outputs (runway and an operant progressive ratio 3 task). Peripheral injections of naloxone or flupenthixol were administered when these tasks were learned and stable.Naloxone decreased food intake when pellets were palatable, while flupenthixol was without any effect. When considering motivation, naloxone decreased performances in both the runway and progressive ratio tests while flupenthixol was only effective in the progressive ratio test.Impairing the opioid neurotransmission diminishes motivation to obtain food, possibly through a decrease in the perceived palatability of the food reward. The dopaminergic system appears to be more involved in the modulation of motivation to obtain food in a cost/benefit-related manner.