It was once believed that the brain wasindependent of metabolic processes （代谢过程）occurring elsewhere in the body.
曾经的理论（应该是作者不同意的理论）：大脑的新陈代谢过程是单独的
Inrecent studies, however,we have discovered that the production and release in brain neurons of theneurotransmitter serotonin (neurotransmitters are compounds that neurons use totransmit signals to other cells) depend directly on the food that the bodyprocesses.
现在的研究：大脑神经的neuro serotonin的生产和释放直接和身体吃的食物有关
Our first studies sought to determinewhether the increase in serotonin observed in rats given a large injection ofthe amino acid tryptophan might also occur after rats ate meals that changetryptophan levels in the blood.
第一个实验：在小白鼠接受了大量amino acid tryptophan之后，serotonin会上升这个情况是否也会在小白鼠吃了会改变血液tryptophan水平的饭之后发生。
We found that, immediately after the ratsbegan to eat, parallel elevations occurred in blood tryptophan, braintryptophan, and brain serotonin levels.
小白鼠吃完以后，血液tryptophan，大脑tryptophan和大脑serotonin 水平全都会上升
These findings suggested that theproduction and release of serotonin in brain neurons were normally coupled withblood-tryptophan increases.
这些都表现出了大脑神经元的serotonin生产和释放经常伴随着血液tryptophan上升
Inlater studies we found that injecting insulin into a rat’s bloodstream alsocaused parallel elevations in blood and brain tryptophan levels and inserotonin levels.
后来的实验发现给小白鼠血液注射insulin也会导致血液和大脑的tryptophan和 serotonin水平上升
Wethen decided to see whether the secretion of the animal’s own insulin similarlyaffected serotonin production.
之后来看动物自己的insulin分泌物会不会也类似的影响serotonin生产
Wegave the rats a carbohydrate-containing meal that we knew would elicit insulinsecretion. As we had hypothesized, the blood tryptophan level and theconcentrations of tryptophan and of serotonin in the brain increased after themeal.
给小白鼠吃carbohydrate-containing的饭，这种饭会引起insulin secretion。如我们假设。血液tryptophan水平，浓度，大脑serotonin在饭后立刻上升了
Surprisingly, however, when we added a large amount of proteinto the meal, brain tryptophan and serotonin levels fell.
令人惊奇的是，当我们加入了在饭里加入了大量蛋白质，大脑tryptophan 和serotonin水平下降了
Since protein contains tryptophan, whyshould it depress brain tryptophan levels?
蛋白质里含有tryptophan，为什么还会压制大脑tryptophan水平？
The answer lies in the mechanism thatprovides blood tryptophan to the brain cells.
答案就在提供血液tryptophan和大脑细胞的机制里
This same mechanism also provides the braincells with other amino acids found in protein, such as tyrosine and leucine.
这个机制也提供和其他amino acids一起在蛋白质里被发现的大脑细胞，比如tyrosine and leucine.
The consumption of protein increases bloodconcentration of the other amino acids much more, proportionately, than it doesthat of tryptophan.
蛋白质消耗增长了很多其它amino acids的血液浓度，相对于tryptophan的血液浓度来说
The more protein is in a meal, the lower isthe ratio of the resulting blood-tryptophan concentration to the concentrationof competing amino acids, and the more slowly is tryptophan provided to thebrain.
饭里的蛋白质越多，血液tryptophan浓度和aminoacids浓度的比例就越低，tryptophan越慢地提供给大脑
Thus the more protein in a meal, the lessserotonin subsequently produced and released.
所以，饭里的蛋白质越多，越少的serotonin被生产和释放
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发表于 2016-5-31 22:06:20
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