Increased enkephalin in brain of rats prone to overconsuming a fat-rich diet
Increased enkephalin in brain of rats prone to overconsuming a fat-rich diet
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DOI：
10.1016/j.physbeh.2010.06.005
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发表时间：
2010-10-05
影响因子：
2.9
通讯作者：
Leibowitz, S. F.
中科院分区：
文献类型：
--
作者：
Chang, G. -Q.;Karatayev, O.;Leibowitz, S. F.
最近的研究表明，阿片类脑啡肽（ENK）部分通过下丘脑室旁核（PVN）发挥作用，可以刺激高脂肪饮食的消耗。本研究的目的是检查自然容易过度摄入高脂肪饮食的 Sprague-Dawley 大鼠亚群，并确定这些动物不同大脑区域的内源性 ENK 是否发生改变，并可能导致其行为表型。一种动物模型，包括在几天的访问期间测量初始高脂肪饮食摄入量，以预测长期摄入量，旨在将正常体重的大鼠分类为高脂肪消费者（HFC），其摄入的高脂肪热量比低脂食物多35％，或对照组，其消耗这两种饮食的相似热量。在首次摄入饮食后，与对照大鼠相比，HFC 大鼠在 PVN、伏核和杏仁核中央核中表现出明显更高的 ENK mRNA 表达，但在弓状核或基底外侧杏仁核中则没有。即使 HFC 大鼠维持普通饮食，ENK 的这种位点特异性增加仍然持续存在，这表明它反映了一种可以独立于饮食而表达的固有特征。与食用高脂肪饮食的生理盐水相比，HFC 大鼠对注射 PVN 的 ENK 类似物 D-ala2-met-脑啡酰胺的刺激作用的反应性更强。因此，预计过度食用富含脂肪的饮食的正常体重大鼠会表现出内源性 ENK 表达和功能的紊乱，这可能有助于其长期行为表型。 (C) 2010 Elsevier Inc. 保留所有权利。
Recent studies have shown that the opioid enkephalin (ENK), acting in part through the hypothalamic paraventricular nucleus (PVN), can stimulate consumption of a high-fat diet. The objective of the present study was to examine sub-populations of Sprague-Dawley rats naturally prone to overconsuming a high-fat diet and determine whether endogenous ENK, in different brain regions, is altered in these animals and possibly contributes to their behavioral phenotype. An animal model, involving a measure of initial high-fat diet intake during a few days of access that predicts long-term intake, was designed to classify rats at normal weight that are either high-fat consumers (HFC), which ingest 35% more calories of the high-fat than low-fat chow diet, or controls, which consume similar calories of these two diets. Immediately after their initial access to the diet, the HFC compared to control rats exhibited significantly greater expression of ENK mRNA, in the PVN, nucleus accumbens and central nucleus of the amygdala, but not the arcuate nucleus or basolateral amygdala. This site-specific increase in ENK persisted even when the HFC rats were maintained on a chow diet, suggesting that it reflects an inherent characteristic that can be expressed independently of the diet. It was also accompanied by a greater responsiveness of the HFC rats to the stimulatory effect of a PVN-injected, ENK analogue, D-ala2-met-enkephalinamide, compared to saline on consumption of the high-fat diet. Thus, normal-weight rats predicted to overconsume a fat-rich diet exhibit disturbances in endogenous ENK expression and functioning that may contribute to their long-term, behavioral phenotype. (C) 2010 Elsevier Inc. All rights reserved.