The Protein Status of Rats Affects the Rewarding Value of Meals Due to their Protein Content
The Protein Status of Rats Affects the Rewarding Value of Meals Due to their Protein Content
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DOI：
10.1093/jn/nxy060
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发表时间：
2018-06-01
影响因子：
4.2
通讯作者：
Tome, Daniel
中科院分区：
文献类型：
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作者：
Chaumontet, Catherine;Recio, Isidra;Tome, Daniel
背景资料：蛋白质状态由大脑控制，大脑调节进食行为以防止蛋白质deficiency.Objective：本研究在大鼠中测试蛋白质状态是否通过大脑奖励pathways.Methods：在雄性Wistar大鼠（平均+/- SD体重; 230 +/- 16 g）中进行实验。在实验1中，大鼠适应低蛋白（LP; 6%的能量）或正常蛋白（NP; 14%的能量）饮食2周，提供3杯高蛋白（HP; 50%的能量），NP或LP饲料之间的选择;他们的摄入量进行了24小时的测量。在另外2个实验中，使大鼠适应NP和HP或LP饮食2周，并在过夜禁食后每天接受校准的HP、NP或LP膳食。在最后一天的进餐后，处死大鼠，测定身体组成和血液蛋白、甘油三酯、肠神经肽和激素。在脑中，下丘脑中的神经肽mRNAs和延髓核（NAcc）中的c-Fos蛋白以及阿片和多巴胺能受体mRNAs被测量。结果：在选择实验中，与NP饮食相比，饲喂LP的大鼠体重降低7%，蛋白质摄入量显著增加（平均值+/- SD：30.5% +/-0.05%与能量的20.5% +/- 0.05%相比）、较高的饲料剥夺血饥饿素、较低的餐后血瘦素、以及较高的下丘脑神经肽Y（Npy）和促肾上腺皮质激素释放激素（Crh）mRNA表达。与NP相比，饲喂LP饮食的大鼠在NAcc中显示餐后c-Fos蛋白表达，这在两餐之间存在显著差异，LP < NP < HP。相比之下，在适应HP饮食的大鼠中，与NP饮食相比，能量摄入较低;在NAcc中，膳食诱导的c-Fos蛋白表达降低20%，多巴胺受体2（Drd 2）受体的mRNA表达升高17%，κ阿片受体（Oprk 1）受体的mRNA表达降低38%。蛋白质限制饮食诱导奖赏系统驱动的蛋白质食欲，而富含蛋白质的饮食减少了雄性大鼠中膳食诱导的奖赏途径激活，并降低了能量摄入。
Background: Protein status is controlled by the brain, which modulates feeding behavior to prevent protein deficiency.Objective: This study tested in rats whether protein status modulates feeding behavior through brain reward pathways.Methods: Experiments were conducted in male Wistar rats (mean +/- SD weight; 230 +/- 16 g). In experiment 1, rats adapted for 2 wk to a low-protein (LP; 6% of energy) or a normal-protein (NP; 14% of energy) diet were offered a choice between 3 cups containing high-protein (HP; 50% of energy), NP, or LP feed; their intake was measured for 24 h. In 2 other experiments, the rats were adapted for 2 wk to NP and either HP or LP diets and received, after overnight feed deprivation, a calibrated HP, NP, or LP meal daily. After the meal, on the last day, rats were killed and body composition and blood protein, triglycerides, gut neuropeptides, and hormones were determined. In the brain, neuropeptide mRNAs in the hypothalamus and c-Fos protein and opioid and dopaminergic receptor mRNAs in the nucleus accumbens (NAcc) were measured.Results: Rats fed an LP compared with an NP diet had 7% lower body weight, significantly higher protein intake in a choice experiment (mean +/- SD: 30.5% +/- 0.05% compared with 20.5% +/- 0.05% of energy), higher feed-deprived blood ghrelin, lower postmeal blood leptin, and higher neuropeptide Y (Npy) and corticotropin-releasing hormone (Crh) mRNA expression in the hypothalamus. In contrast to NP, rats fed an LP diet showed postmeal c-Fos protein expression in the NAcc, which was significantly different between meals, with LP < NP < HP. In contrast, in rats adapted to an HP diet compared with an NP diet, energy intake was lower; and in the NAcc, meal-induced c-Fos protein expression was 20% lower, and mRNA expression was 17% higher for dopamine receptor 2 (Drd2) receptors and 38% lower for kappa opioid receptor (Oprk1) receptors.Conclusions: A protein-restricted diet induced a reward system-driven appetite for protein, whereas a protein-rich diet reduced the meal-induced activation of reward pathways and lowered energy intake in male rats.