生物谷报道：蒙特利尔麦吉尔大学研究人员7日在Cell Metabolism上面发表论文称发现了一些人难于抵御食物诱惑的原因。研究显示，饥饿时身体会分泌一种激素，这种激素会让食物看起来更加诱人。这种“饥饿激素”作用于大脑，同样提高了我们注意个别食物的能力，最终把它们留在记忆中。让食物变得更难于抵御。
在一项旨在为研制新减肥药铺平道路的研究中，研究人员利用大脑扫描技术，验证ghrelin将对健康的年轻参与者产生何种影响。研究中，他向参与者展示了汉堡、比萨以及风景图片。相对于风景图片来说，食物图片能够让注射ghrelin的参与者负责快乐感的大脑区域受到更大刺激。在试验即将结束时，达格赫又向参与者展示了食物图片，并让他们从中挑选出自己曾经看到过的图片。这一次，注射ghrelin的参与者再次胜出，他们能够更为准确地完成挑选任务。
蒙特利尔麦吉尔大学神经病学家达格赫说：“ghrelin会产生广泛影响。它不仅作用于大脑的一个或者两个区域，而是整个大脑。食物照片变得更为显眼，人们真的认为这些照片更具诱惑力。ghrelin不仅影响视觉处理，同时也会影响记忆。当处于较高水平时，人们能够更好地回忆起食物照片。”
重要的是，这种大脑活动形态与毒瘾研究的发现存在类似之处。之前的研究显示，ghrelin促使我们摄入比平时更多的热量，形象地说，吃垃圾食品上瘾的人很可能是这种激素在作怪。（生物谷www.bioon.com）
生物谷推荐原始出处：
Cell Metabolism, Vol 7, 400-409, 07 May 2008
Ghrelin Modulates Brain Activity in Areas that Control Appetitive Behavior
Saima Malik,1 Francis McGlone,2 Diane Bedrossian,1 and Alain Dagher1,
1 Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
2 Unilever R&D, Wirral, Cheshire CH63 3JW, UK
Corresponding author
Summary
Feeding behavior is often separated into homeostatic and hedonic components. Hedonic feeding, which can be triggered by visual or olfactory food cues, involves brain regions that play a role in reward and motivation, while homeostatic feeding is thought to be under the control of circulating hormones acting primarily on the hypothalamus. Ghrelin is a peptide hormone secreted by the gut that causes hunger and food consumption. Here, we show that ghrelin administered intravenously to healthy volunteers during functional magnetic resonance imaging increased the neural response to food pictures in regions of the brain, including the amygdala, orbitofrontal cortex, anterior insula, and striatum, implicated in encoding the incentive value of food cues. The effects of ghrelin on the amygdala and OFC response were correlated with self-rated hunger ratings. This demonstrates that metabolic signals such as ghrelin may favor food consumption by enhancing the hedonic and incentive responses to food-related cues.
