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orexin
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.
不久前的一个下午,我又困倒了。充满倦意、行动迟缓的我抓了一块巧克力塞进嘴里。但也许我应该吃一些蛋白或是一块牛排。因为一项最近的研究发现,能使小白鼠亢奋的是蛋白质而非糖份。 作为脑细胞的一种,阿里新细胞分泌一种刺激让我们充满活力,并给身体指示燃烧卡路里。如果这种细胞的活力下降,就会犯困瞌睡。这份研究发表于“神经元”期刊。 科学家在小白鼠脑子里标记了阿里新细胞,使它们荧光可见。然后通过喂食给小白鼠不同的食物,来观察这些细胞的活动情况。 于是发现葡萄糖阻碍了阿里新细胞的正常功能。这可能就是午后犯困的主要原因了。但研究者也发现氨基酸能阻止葡萄糖的行动,保持阿里新细胞有活力,从而使小白鼠警醒。所以下次在下午3点犯困的时候,我会吃个鸡蛋。前提是我还足够清醒能记住这个研究结果。