Pepino Marta Y, Eisenstein Sarah A, Bischoff Allison N, Klein Samuel, Moerlein Stephen M, Perlmutter Joel S, Black Kevin J, Hershey Tamara
Atkins Center of Excellence in Obesity Medicine, Center for Human Nutrition, Washington University School of Medicine in St. Louis, St. Louis, MO
Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, MO Department of Radiology, Washington University School of Medicine in St. Louis, St. Louis, MO.
Diabetes. 2016 Sep;65(9):2618-23. doi: 10.2337/db16-0407. Epub 2016 Jun 15.
Alterations in dopaminergic circuitry play a critical role in food reward and may contribute to susceptibility to obesity. Ingestion of sweets releases dopamine in striatum, and both sweet preferences and striatal D2 receptors (D2R) decline with age and may be altered in obesity. Understanding the relationships between these variables and the impact of obesity on these relationships may reveal insight into the neurobiological basis of sweet preferences. We evaluated sucrose preferences, perception of sweetness intensity, and striatal D2R binding potential (D2R BPND) using positron emission tomography with a D2R-selective radioligand insensitive to endogenous dopamine, (N-[(11)C] methyl)benperidol, in 20 subjects without obesity (BMI 22.5 ± 2.4 kg/m(2); age 28.3 ± 5.4 years) and 24 subjects with obesity (BMI 40.3 ± 5.0 kg/m(2); age 31.2 ± 6.3 years). The groups had similar sucrose preferences, sweetness intensity perception, striatal D2R BPND, and age-related D2R BPND declines. However, both striatal D2R BPND and age correlated with sucrose preferences in subjects without obesity, explaining 52% of their variance in sucrose preference. In contrast, these associations were absent in the obese group. In conclusion, the age-related decline in D2R was not linked to the age-related decline in sweetness preferences, suggesting that other, as-yet-unknown mechanisms play a role and that these mechanisms are disrupted in obesity.
多巴胺能神经回路的改变在食物奖赏中起关键作用,可能导致肥胖易感性。摄入甜食会使纹状体释放多巴胺,甜味偏好和纹状体D2受体(D2R)均会随年龄下降,且在肥胖状态下可能发生改变。了解这些变量之间的关系以及肥胖对这些关系的影响,可能会揭示甜味偏好的神经生物学基础。我们使用对内源性多巴胺不敏感的D2R选择性放射性配体(N-[(11)C]甲基)苯哌利多,通过正电子发射断层扫描评估了20名非肥胖受试者(BMI 22.5±2.4 kg/m²;年龄28.3±5.4岁)和24名肥胖受试者(BMI 40.3±5.0 kg/m²;年龄31.2±6.3岁)的蔗糖偏好、甜味强度感知和纹状体D2R结合潜能(D2R BPND)。两组在蔗糖偏好、甜味强度感知、纹状体D2R BPND以及与年龄相关的D2R BPND下降方面相似。然而,在非肥胖受试者中,纹状体D2R BPND和年龄均与蔗糖偏好相关,解释了其蔗糖偏好变异的52%。相比之下,肥胖组中不存在这些关联。总之,D2R与年龄相关的下降与甜味偏好与年龄相关的下降无关,这表明其他尚未明确的机制起了作用,且这些机制在肥胖状态下受到了破坏。