Key Laboratory of Measurement and Evaluation in Human Movement and Bioinformation, Physical Education College , Hebei Normal University , Shijiazhuang , Hebei 050024 , China.
Department of Health Science , Xi'an Sport University , Xi'an 817006 , China.
ACS Chem Neurosci. 2019 Jun 19;10(6):2801-2808. doi: 10.1021/acschemneuro.9b00022. Epub 2019 May 1.
The dopaminergic pathway, comprising projections from the ventral tegmental area to the nucleus accumbens, constitutes the core of the brain reward system. Insufficient food reward caused by dopamine signaling dysfunction in the nucleus accumbens is an important contributor to obesity and may be associated with insulin signaling. Aerobic exercise has a positive effect on both preventing and treating obesity. In addition, physical exercise is important in striatal dopamine homeostasis and improves insulin sensitivity in the peripheral and central nervous system. Therefore, we hypothesized that aerobic exercise may increase dopamine levels in the nucleus accumbens through insulin signaling, thus improving food reward in obesity. In the present study, we used a rat model of obesity, induced by high fat diet. Obese rats exhibited lower basic dopamine concentration in the nucleus accumbens induced by eating or extracellular insulin, attenuated insulin signaling, and increased fat preference. Interestingly, an 8-week aerobic exercise regimen reversed these symptoms. In addition, we noted a significant increase in insulin Akt/GSK3-β signal transduction in the nucleus accumbens. These data demonstrate that aerobic exercise promotes dopamine levels in the nucleus accumbens through insulin signal transduction, which may constitute an important neurobiological mechanism of exercise against obesity.
多巴胺能通路包括腹侧被盖区到伏隔核的投射，构成了大脑奖励系统的核心。伏隔核中多巴胺信号功能障碍导致的食物奖励不足是肥胖的一个重要诱因，可能与胰岛素信号有关。有氧运动对预防和治疗肥胖都有积极作用。此外，体育锻炼对纹状体多巴胺的动态平衡很重要，并能改善外周和中枢神经系统的胰岛素敏感性。因此，我们假设有氧运动可能通过胰岛素信号增加伏隔核中的多巴胺水平，从而改善肥胖时的食物奖励。在本研究中，我们使用高脂肪饮食诱导的肥胖大鼠模型。肥胖大鼠在进食或细胞外胰岛素刺激下，伏隔核中多巴胺的基础浓度降低，胰岛素信号减弱，脂肪偏好增加。有趣的是，8 周的有氧运动方案逆转了这些症状。此外，我们注意到伏隔核中胰岛素 Akt/GSK3-β信号转导显著增加。这些数据表明，有氧运动通过胰岛素信号转导促进伏隔核中的多巴胺水平，这可能构成运动对抗肥胖的重要神经生物学机制。
