Laboratory of Metabolism, Division of Endocrinology, Diabetology and Nutrition, Department of Internal Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Physiol Behav. 2010 Sep 1;101(2):277-81. doi: 10.1016/j.physbeh.2010.05.017. Epub 2010 Jun 1.
Ghrelin is one of the most potent orexigens known to date. While the prevailing view is that ghrelin participates in the homeostatic control of feeding, the question arose as to whether consummatory responses evoked by this compound could be related to search for reward. We therefore attempted to delineate the involvement of ghrelin in the modulation of non-caloric but highly rewarding consumption.
We tested the effect of intraperitoneally injected ghrelin on the acceptance and preference for a 0.3% saccharin solution using single bottle tests and free-choice preference test procedures in C57BL6/J mice, as well as in mice lacking the ghrelin receptor (GHSR1a -/-) and their wild-type (WT) littermates.
In the single bottle tests, peripheral ghrelin consistently increased the consumption of saccharin, independently of availability of caloric food. In the free-choice preference test procedures, ghrelin increased the preference for saccharin in WT mice, while it did had not effect in GHSR1a -/-animals, indicating that the ghrelin receptor pathway is necessary to mediate this parameter.
Peripheral ghrelin enhances intake and preference for a sweet food, regardless of whether the food has caloric content. This effect, mediated through the ghrelin receptor pathway, may serve as additional enhancers of energy intake.
胃饥饿素是迄今为止已知的最有效的食欲刺激素之一。虽然普遍观点认为胃饥饿素参与了进食的体内平衡控制，但人们提出了一个问题，即这种化合物引起的摄食反应是否与寻找奖励有关。因此，我们试图阐明胃饥饿素在调节非热量但极具吸引力的消费中的作用。
我们使用单瓶测试和自由选择偏好测试程序，在 C57BL6/J 小鼠以及缺乏胃饥饿素受体（GHSR1a-/-）的小鼠及其野生型（WT）同窝仔鼠中，测试了腹腔内注射胃饥饿素对 0.3%蔗糖溶液接受和偏好的影响。
在单瓶测试中，外周胃饥饿素始终增加蔗糖的消耗，而与热量食物的可用性无关。在自由选择偏好测试程序中，胃饥饿素增加了 WT 小鼠对蔗糖的偏好，而在 GHSR1a-/-动物中则没有效果，表明胃饥饿素受体途径是介导这一参数所必需的。
外周胃饥饿素增强了对甜食的摄入和偏好，而不论食物是否具有热量含量。这种通过胃饥饿素受体途径介导的作用可能作为能量摄入的额外增强剂。
