Department of Psychology, University of Illinois-Urbana Champaign, Champaign, IL, USA.
Neuroscience Program, University of Illinois-Urbana Champaign, Champaign, IL, USA.
Nutr Neurosci. 2022 Dec;25(12):2547-2559. doi: 10.1080/1028415X.2021.1986199. Epub 2021 Oct 11.
There is a clear association between obesity and impulsivity. While exercise can suppress weight gain and decrease impulsive choice (IC), the relationship between impulsivity, the consumption of palatable, energy dense diets, and exercise is unclear. We examined IC before and after Western diet (WD) exposure in rats of both sexes and whether exercise would rescue any diet-mediated increases in IC. Our hypotheses were twofold: first, increased impulsivity would be associated with higher WD preference in a positive feedback loop and second, increased WD consumption would impair both peripheral and central insulin signaling, both of which exercise would attenuate.
Following baseline assessment of IC through a delay discounting task, rats were divided into naïve, sedentary (Sed), or wheel running (WR) groups for a 5-week WR and two-diet choice period after which rats underwent an oral glucose (OGTT) and insulin tolerance test (ITT) in addition to a re-test of IC. Insulin induced Akt-GSK3β signaling in the brain was examined using western blot.
All Sed rats preferred the WD diet, and all WR rats initially avoided the WD but subsequently reversed their avoidance to preference with females reversing earlier than males. Exercise suppressed weight gain and adiposity to a greater extent in males than females. Only WR males showed improved glucose clearance during OGTT, but both male and female WR rats had a faster recovery of hypoglycemia during ITT. Furthermore, WR rescued WD-induced deficits in hypothalamic Akt-GSK3β signaling in males but not females. In the prefrontal cortex, however, WD and WR both reduced Akt-GSK3β signaling in males but not females. There were no sex differences in IC at baseline, and all rats made more impulsive choices during the re-test independent of diet, sex, or exercise.
The results suggest that while exercise may have a greater efficacy at attenuating diet-mediated metabolic dysregulation in males, it has some beneficial effects for females and highlights the need to develop sex-specific interventions for restoring energy balance.
肥胖与冲动之间存在明显的关联。虽然运动可以抑制体重增加和减少冲动选择（IC），但冲动、食用美味、高热量饮食和运动之间的关系尚不清楚。我们在雄性和雌性大鼠中检查了暴露于西方饮食（WD）前后的 IC，以及运动是否可以挽救任何饮食介导的 IC 增加。我们的假设有两个方面：首先，冲动增加将与 WD 偏好的正反馈循环相关；其次，WD 消费增加会损害外周和中枢胰岛素信号，运动都可以减轻这些影响。
通过延迟折扣任务对 IC 进行基线评估后，将大鼠分为未处理、久坐（Sed）或轮式跑步（WR）组，进行 5 周的 WR 和两饮食选择期，然后进行口服葡萄糖（OGTT）和胰岛素耐量试验（ITT），以及 IC 的重新测试。使用 Western blot 检查大脑中胰岛素诱导的 Akt-GSK3β信号。
所有 Sed 大鼠都喜欢 WD 饮食，所有 WR 大鼠最初回避 WD，但随后从回避转为偏好，雌性大鼠比雄性大鼠更早转变。运动对雄性大鼠的体重增加和肥胖抑制程度大于雌性大鼠。只有 WR 雄性大鼠在 OGTT 中显示出更好的葡萄糖清除率，但在 ITT 中，雄性和雌性 WR 大鼠的低血糖恢复更快。此外，WR 挽救了 WD 诱导的雄性大鼠下丘脑 Akt-GSK3β信号缺陷，但不能挽救雌性大鼠。然而，在雄性大鼠的前额叶皮层中，WD 和 WR 都降低了 Akt-GSK3β信号，而在雌性大鼠中则没有。在基线时，IC 没有性别差异，所有大鼠在重新测试中都做出了更冲动的选择，无论饮食、性别或运动如何。
结果表明，虽然运动可能在减轻雄性大鼠饮食介导的代谢失调方面更有效，但它对雌性大鼠也有一些有益的影响，这突出了需要开发针对恢复能量平衡的性别特异性干预措施。
