Department of Pharmacology and Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati OH, 45237, USA; Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, SA.
Department of Pharmacology and Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati OH, 45237, USA.
Physiol Behav. 2023 Oct 15;270:114285. doi: 10.1016/j.physbeh.2023.114285. Epub 2023 Jun 29.
Limited intermittent consumption of palatable food reduces HPA axis responses to stress in chow-fed rats, and this effect is dependent on the rewarding properties of the palatable food. However, obesity may be a state of reduced consummatory food reward, suggesting that palatable foods may be less effective at blunting HPA axis reactivity in the context of diet-induced obesity (DIO). To test this hypothesis, adult male Long-Evans rats were given unlimited access to Western (high-fat, high-sugar) diet (WD) vs. normal chow (controls). After 8 weeks of diet exposure, rats were given limited sucrose intake (LSI) consisting of additional twice-daily access to a small amount (4 ml) of either 3% or 30% sucrose drink, or water (controls) for 2 weeks. Rats then received an acute restraint stress challenge, with collection of tail blood samples for measurement of plasma corticosterone. WD-fed rats had increased caloric intake, body weight and adiposity, as expected. Rats offered LSI (3% or 30%) readily drank the maximal amount allowed (8 ml/day) and reduced their dietary intake to compensate for the sucrose calories, such that LSI did not alter body weight regardless of diet type. In chow-fed lean rats, LSI with either 3% or 30% sucrose reduced the plasma corticosterone response to restraint stress, but this effect was absent in WD-fed DIO rats. Together, these data support the hypothesis that obesity attenuates stress blunting by palatable foods and suggest the possibility that consequently, individuals with obesity may need to consume larger amounts of palatable food to obtain adequate stress relief.
有限的间歇性摄入美味食物可减少 Chow 喂养的大鼠应激时 HPA 轴的反应，这种作用依赖于美味食物的奖赏特性。然而，肥胖可能是一种摄食奖赏降低的状态，这表明在饮食诱导肥胖（DIO）的情况下，美味食物可能不太能有效地抑制 HPA 轴的反应。为了验证这一假设，成年雄性 Long-Evans 大鼠给予无限制地摄入西式（高脂肪、高糖）饮食（WD）与正常饲料（对照）。在 8 周的饮食暴露后，大鼠给予有限的蔗糖摄入（LSI），即每天两次额外摄入少量（4ml）3%或 30%蔗糖饮料或水（对照）2 周。然后，大鼠接受急性束缚应激挑战，采集尾血样测量血浆皮质酮。如预期的那样，WD 喂养的大鼠热量摄入、体重和肥胖增加。提供 LSI（3%或 30%）的大鼠很容易饮用允许的最大量（8ml/天），并减少其饮食摄入量以补偿蔗糖热量，因此无论饮食类型如何，LSI 都不会改变体重。在 Chow 喂养的瘦大鼠中，3%或 30%的蔗糖 LSI 均可减少束缚应激时的血浆皮质酮反应，但在 WD 喂养的 DIO 大鼠中，这种作用消失。总之，这些数据支持肥胖症减弱美味食物对压力的缓冲作用的假设，并表明肥胖症个体可能需要摄入更多的美味食物才能获得足够的压力缓解。
