生物谷報(bào)道：蒙特利爾麥吉爾大學(xué)研究人員7日在Cell Metabolism上面發(fā)表論文稱發(fā)現(xiàn)了一些人難于抵御食物誘惑的原因。研究顯示,，饑餓時(shí)身體會(huì)分泌一種激素,，這種激素會(huì)讓食物看起來(lái)更加誘人,。這種“饑餓激素”作用于大腦，同樣提高了我們注意個(gè)別食物的能力,，最終把它們留在記憶中,。讓食物變得更難于抵御。
在一項(xiàng)旨在為研制新減肥藥鋪平道路的研究中,，研究人員利用大腦掃描技術(shù),，驗(yàn)證ghrelin將對(duì)健康的年輕參與者產(chǎn)生何種影響。研究中,，他向參與者展示了漢堡,、比薩以及風(fēng)景圖片。相對(duì)于風(fēng)景圖片來(lái)說(shuō),，食物圖片能夠讓注射ghrelin的參與者負(fù)責(zé)快樂(lè)感的大腦區(qū)域受到更大刺激,。在試驗(yàn)即將結(jié)束時(shí)，達(dá)格赫又向參與者展示了食物圖片,，并讓他們從中挑選出自己曾經(jīng)看到過(guò)的圖片,。這一次，注射ghrelin的參與者再次勝出,，他們能夠更為準(zhǔn)確地完成挑選任務(wù),。
蒙特利爾麥吉爾大學(xué)神經(jīng)病學(xué)家達(dá)格赫說(shuō)：“ghrelin會(huì)產(chǎn)生廣泛影響。它不僅作用于大腦的一個(gè)或者兩個(gè)區(qū)域,，而是整個(gè)大腦,。食物照片變得更為顯眼，人們真的認(rèn)為這些照片更具誘惑力。ghrelin不僅影響視覺(jué)處理,，同時(shí)也會(huì)影響記憶,。當(dāng)處于較高水平時(shí)，人們能夠更好地回憶起食物照片,。”
重要的是,，這種大腦活動(dòng)形態(tài)與毒癮研究的發(fā)現(xiàn)存在類似之處。之前的研究顯示,，ghrelin促使我們攝入比平時(shí)更多的熱量,，形象地說(shuō)，吃垃圾食品上癮的人很可能是這種激素在作怪,。（生物谷www.bioon.com）
生物谷推薦原始出處：
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.
