Department of Physiology and Pathophysiology, Xian Jiaotong University School of Medicine, Xian, Shaanxi, PR China.
Brain Res. 2010 Apr 14;1325:53-62. doi: 10.1016/j.brainres.2010.02.026. Epub 2010 Feb 12.
Sweet taste usually signifies the presence of caloric food. It is commonly accepted that a close association exists among sweet taste perception, preference, and nutritional status. However, the mechanisms involved remain unknown. To investigate whether nutritional status affects the preference for palatable solutions and alters sweet taste receptor gene expression in rats, we measured saccharin intake and preference using a two-bottle preference test, and changes in body weight, plasma leptin levels, and gene expression for the sweet taste receptor in taste buds in high-fat diet-induced obese rats and chronically diet-restricted rats. We found that the consumption and preference ratios for 0.01 and 0.04 M saccharin were significantly lower in the high-fat diet-induced obese rats than in the normal diet rats, while the serum leptin levels were markedly increased in obese rats. Consistent with the changes in saccharin intake, the gene expression level of the sweet taste receptor T1R3 was significantly decreased in the high-fat diet-induced obese rats compared with the control rats. By contrast, the chronically diet-restricted rats showed remarkably enhanced consumption and preference for 0.04 M saccharin. The serum leptin concentration was decreased, and the gene expression of the leptin receptor was markedly increased in the taste buds. In conclusion, our results suggest that nutritional status alters saccharin preference and the expression of T1R3 in taste buds. These processes may be involved in the mechanisms underlying the modulation of peripheral sweet taste sensitivity, in which leptin plays a role.
甜味通常表示热量食物的存在。人们普遍认为，甜味感知、偏好和营养状况之间存在密切联系。然而，其中涉及的机制仍不清楚。为了研究营养状况是否会影响对美味溶液的偏好，并改变肥胖大鼠和慢性饮食限制大鼠味蕾中甜味受体基因的表达，我们使用双瓶偏好试验测量了蔗糖的摄入量和偏好，以及体重、血浆瘦素水平和味觉中甜味受体基因表达的变化肥胖大鼠和慢性饮食限制大鼠。我们发现，高脂肪饮食诱导的肥胖大鼠对 0.01 和 0.04 M 蔗糖的消耗量和偏好比例明显低于正常饮食大鼠，而肥胖大鼠的血清瘦素水平明显升高。与蔗糖摄入量的变化一致，高脂肪饮食诱导的肥胖大鼠中甜味受体 T1R3 的基因表达水平明显低于对照组大鼠。相比之下，慢性饮食限制大鼠对 0.04 M 蔗糖的消耗量和偏好明显增加。血清瘦素浓度降低，味觉中瘦素受体的基因表达明显增加。总之，我们的结果表明，营养状况改变了蔗糖的偏好和味蕾中 T1R3 的表达。这些过程可能涉及调节外周甜味敏感性的机制，其中瘦素起着作用。
