Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA.
Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA; Psychology Department (Biopsychology Area), University of Michigan, Ann Arbor, MI, 48109, USA.
Appetite. 2023 Jul 1;186:106556. doi: 10.1016/j.appet.2023.106556. Epub 2023 Apr 10.
Overconsumption of sugar contributes to obesity in part by changing the activity of brain areas that drive the motivation to seek out and consume food. Sugar-sweetened beverages are the most common source of excess dietary sugar and contribute to weight gain. However, very few studies have assessed the effects of liquid sucrose consumption on motivation. This is due in part to the need for novel approaches to assess motivation in pre-clinical models. To address this, we developed a within-session behavioral economics procedure to assess motivation for liquid sucrose. We first established and validated the procedure: we tested several sucrose concentrations, evaluated sensitivity of the procedure to satiety, and optimized several testing parameters. We then applied this new procedure to determine how intermittent vs. continuous access to liquid sucrose (1 M) in the home cage affects sucrose motivation. We found that intermittent liquid sucrose access results in an escalation of sucrose intake in the home cage, without altering motivation for liquid sucrose during demand testing (1 M or 0.25 M) compared to water-maintained controls. In contrast, continuous home cage access selectively blunted motivation for 1 M sucrose, while motivation for 0.25 M sucrose was similar to intermittent sucrose and control groups. Thus, effects of continuous home cage liquid sucrose access were selective to the familiar sucrose concentration. Finally, effects of sucrose on motivation recovered after removal of liquid sucrose from the diet. These data provide a new approach to examine motivation for liquid sucrose and show that escalation of intake and motivation for sucrose are dissociable processes.
过量摄入糖分会导致肥胖，部分原因是改变了驱动寻找和摄入食物的大脑区域的活动。含糖饮料是过量摄入膳食糖的最常见来源，并导致体重增加。然而，很少有研究评估液体蔗糖消耗对动机的影响。这部分是由于需要新的方法来评估临床前模型中的动机。为了解决这个问题，我们开发了一种在单次会话中评估液体蔗糖动机的行为经济学程序。我们首先建立并验证了该程序：我们测试了几种蔗糖浓度，评估了该程序对饱腹感的敏感性，并优化了几种测试参数。然后，我们应用这种新程序来确定间歇与连续在家中获取液体蔗糖（1 M）如何影响蔗糖动机。我们发现，与水维持对照组相比，间歇性液体蔗糖摄入会导致在家中摄入蔗糖量增加，但在需求测试（1 M 或 0.25 M）中不会改变对液体蔗糖的动机。相比之下，连续的家笼液体蔗糖摄入会选择性地削弱对 1 M 蔗糖的动机，而对 0.25 M 蔗糖的动机则与间歇性蔗糖和对照组相似。因此，连续家笼液体蔗糖摄入的影响是针对熟悉的蔗糖浓度的。最后，从饮食中去除液体蔗糖后，蔗糖对动机的影响恢复。这些数据提供了一种新的方法来检查液体蔗糖的动机，并表明摄入和蔗糖动机的增加是可分离的过程。
