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the journal Neuron
siesta
The other afternoon I hit a classic mid-afternoon slump. Sleepy and sluggish, I grabbed for a bit of chocolate. But I probably should have had egg whites or maybe a piece of steak. Because a recent study in mice has found that it's protein, not sugar, that provides the perk. Brain cells called orexin cells secrete a stimulant that makes us energetic and tells the body to burn calories. If the cells' activity decreases, narcolepsy or sudden sleepiness, is the result. The work is published in the journal Neuron. Scientists marked orexin cells in mice brains so they would fluoresce. Then they tracked the cells' activity after feeding the mice different kinds of food. Turns out that glucose blocks the function of the orexin cells. This effect might be the main reason for the desired post-lunch siesta. But the researchers also found that amino acids stop the glucose action, keeping the cells active and the mice alert. So next time I get that 3 p.m. slow down, I'll have an egg. If I'm alert enough to remember.
不久前的一個下午，我又困倒了。充滿倦意、行動遲緩的我抓了一塊巧克力塞進(jìn)嘴里。但也許我應(yīng)該吃一些蛋白或是一塊牛排。因?yàn)橐豁椬罱难芯堪l(fā)現(xiàn)，能使小白鼠亢奮的是蛋白質(zhì)而非糖份。 作為腦細(xì)胞的一種，阿里新細(xì)胞分泌一種刺激讓我們充滿活力，并給身體指示燃燒卡路里。如果這種細(xì)胞的活力下降，就會犯困瞌睡。這份研究發(fā)表于“神經(jīng)元”期刊。 科學(xué)家在小白鼠腦子里標(biāo)記了阿里新細(xì)胞，使它們熒光可見。然后通過喂食給小白鼠不同的食物，來觀察這些細(xì)胞的活動情況。 于是發(fā)現(xiàn)葡萄糖阻礙了阿里新細(xì)胞的正常功能。這可能就是午后犯困的主要原因了。但研究者也發(fā)現(xiàn)氨基酸能阻止葡萄糖的行動，保持阿里新細(xì)胞有活力，從而使小白鼠警醒。所以下次在下午3點(diǎn)犯困的時候，我會吃個雞蛋。前提是我還足夠清醒能記住這個研究結(jié)果。