[医学][脑科学]PNAS：大脑为避免负面情绪和焦虑强迫进食

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转自生物谷

反复打破节食的个体所触发的大脑系统可能与造成毒品与酒精成瘾的大脑系统相同。促肾上腺皮质激素释放因子（CRF）大脑应激系统涉及了动机以及物质依赖循环，诸如戒毒或戒酒然后复发的循环，这促使Pietro Cottone及其同事检查了一个节食-暴饮暴食的循环是否会激活大鼠的CRF脑系统。

这组科学家证明了，在这种动物在食用了标准的大鼠食谱5天之后，又紧接着食用了2天高糖、巧克力风味的食物之后，这些大鼠拒绝使用标准食谱，相反，它们过度食用这种甜食。这组作者观察到了大鼠从食用非常可口的饮食到节食的过程中大鼠的杏仁核的CRF基因表达增加，就像大鼠经历戒毒和解酒那样。CRF活性的增加引发了一种负面的精神状态，后者表现为焦虑的迹象以及食用常规食物的动机减少。

这组科学家证明了他们可以通过阻断CRF系统从而阻止这些负面情绪。这组作者说，这些发现提示，人类的强迫进食可能是被避免负面情绪和焦虑的渴望所驱动的，而在两种饮食极端之间的循环可能影响人们的动机。


PNAS November 9, 2009, doi: 10.1073/pnas.0908789106

CRF system recruitment mediates dark side of compulsive eating

Pietro Cottonea,b,c,d,1,2, Valentina Sabinoa,b,c,d,1, Marisa Robertoa,c,d, Michal Bajoe, Lara Pockrosa, Jennifer B. Frihaufa,c,d,f, Eva M. Feketea,c,d, Luca Steardog, Kenner C. Riceh, Dimitri E. Grigoriadisi, Bruno Contid,e, George F. Kooba,c and Eric P. Zorrillaa,c,d,2

aCommittee on the Neurobiology of Addictive Disorders,
cPearson Center for Alcoholism and Addiction Research,
dHarold L. Dorris Neurological Research Institute, and
eDepartment of Molecular and Integrative Neurosciences, The Scripps Research Institute, La Jolla, CA 92037;
bLaboratory of Addictive Disorders, Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118;
fNeuroscience Graduate Program, University of California San Diego, La Jolla, CA 92093;
gDepartment of Human Physiology and Pharmacology, University of Rome La Sapienza, 00185 Rome, Italy;
hChemical Biology Research Branch, National Institute on Drug Abuse and National Institute on Alcohol and Alcoholism, Rockville, MD 20892; and
iNeurocrine Biosciences Inc., San Diego, CA 92130

Dieting to control body weight involves cycles of deprivation from palatable food that can promote compulsive eating. The present study shows that rats withdrawn from intermittent access to palatable food exhibit overeating of palatable food upon renewed access and an affective withdrawal-like state characterized by corticotropin-releasing factor-1 (CRF1) receptor antagonist-reversible behaviors, including hypophagia, motivational deficits to obtain less palatable food, and anxiogenic-like behavior. Withdrawal was accompanied by increased CRF expression and CRF1 electrophysiological responsiveness in the central nucleus of the amygdala. We propose that recruitment of anti-reward extrahypothalamic CRF-CRF1 systems during withdrawal from palatable food, analogous to abstinence from abused drugs, may promote compulsive selection of palatable food, undereating of healthier alternatives, and a negative emotional state when intake of palatable food is prevented.