Gastric bypass in rats does not decrease appetitive behavior towards sweet or fatty fluids despite blunting preferential intake of sugar and fat
Gastric bypass in rats does not decrease appetitive behavior towards sweet or fatty fluids despite blunting preferential intake of sugar and fat
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DOI：
10.1016/j.physbeh.2015.02.004
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发表时间：
2015-04-01
影响因子：
2.9
通讯作者：
Spector, Alan C.
中科院分区：
文献类型：
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作者：
Mathes, Clare M.;Bohnenkamp, Ryan A.;Spector, Alan C.
Roux-en-Y 胃绕道手术 (RYGB) 手术后，患者报告摄入的脂肪和甜点类食物减少，老鼠对糖和脂肪的偏好也减弱。在这里，我们在大鼠模型中使用渐进比率（PR）任务来明确测试 RYGB 是否会降低大鼠对极少量首选含糖和/或脂肪液体的工作意愿。在两项研究中，两组大鼠——一组维持高脂饮食 (HFD) 和标准食物 (CHOW)，另一组仅给予 CHOW——在缺水的情况下接受训练，以按照越来越困难的操作计划获取水或 Ensure 或 1.0 M 蔗糖。在手术前未剥夺条件下进行测试时，HFD 大鼠对蔗糖的 PR 断点（最后强化比例中的操作反应数量）低于 CHOW 大鼠，但对 Ensure 则不然。手术后，给予 RYGB 的大鼠在任何时候都没有表现出比使用 Ensure、蔗糖或术后使用 5% Intralipid 作为强化剂的 SHAM 大鼠更低的断点。然而，在两瓶偏好测试中，RYGB 大鼠对这些热量液体的偏好与对水的偏好不同。重要的是，尽管随着时间的推移，RYGB 大鼠的脂肪乳和蔗糖偏好进一步下降，但它们随后的断点并未受到显着影响。总的来说，这些数据表明，在 RYGB 后观察到的大鼠对正常可口液体的较低偏好可能反映了对改变的食后反馈的习得调整，而不是通过 PR 任务测量的此类刺激的增强味觉特征的抑制，其中食后刺激可以忽略不计。 (C) 2015 Elsevier Inc. 保留所有权利。
After Roux-en-Y gastric bypass (RYGB) surgery, patients report consuming fewer fatty and dessert-like foods, and rats display blunted sugar and fat preferences. Here we used a progressive ratio (PR) task in our rat model to explicitly test whether RYGB decreases the willingness of rats to work for very small amounts of preferred sugar-and/or fat-containing fluids. In each of two studies, two groups of rats - one maintained on a high-fat diet (HFD) and standard chow (CHOW) and one given CHOW alone - were trained while water-deprived to work for water or either Ensure or 1.0 M sucrose on increasingly difficult operant schedules. When tested before surgery while nondeprived, HFD rats had lower PR breakpoints (number of operant responses in the last reinforced ratio) for sucrose, but not for Ensure, than CHOW rats. After surgery, at no time did rats given RYGB show lower breakpoints than SHAM rats for Ensure, sucrose, or when 5% Intralipid served postoperatively as the reinforcer. Nevertheless, RYGB rats showed blunted preferences for these caloric fluids versus water in 2-bottle preference tests. Importantly, although the Intralipid and sucrose preferences of RYGB rats decreased further overtime, subsequent breakpoints for them were not significantly impacted. Collectively, these data suggest that the observed lower preferences for normally palatable fluids after RYGB in rats may reflect a learned adjustment to altered postingestive feedback rather than a dampening of the reinforcing taste characteristics of such stimuli as measured by the PR task in which postingestive stimulation is negligible. (C) 2015 Elsevier Inc. All rights reserved.