Tyrosine is needed to synthesize dopamine and norepinephrine, and tryptophan is needed to synthesize the neurotransmitter serotonin.

酪氨酸是合成多巴胺、去甲肾上腺素所必须的；色氨酸是合成神经递质血清素所必须的。

Serotonin is one of the oldest neurotransmitters.

“血清素是最古老的神经递质之一。”

Specifically, the genes that express your serotonin receptors.

更准，是表达血清素受体的基因。

One of those relief-providing chemicals is serotonin, a neurotransmitter.

提供缓解的化物质之一是血清素，一种神经递质。

Patients with schizophrenia often have elevated levels of serotonin in the brain.

患有精神裂症的病人大脑通常拥有较高的血清素水平。

One widespread impression among the public is that depression is caused by having too little serotonin.

公众普遍认为抑郁症是由血清素过少而引起的。

Because MDMA affects serotonin, a nervous system chemical.

这是因为MDMA会影响一种名为“血清素”的神经系统化物质。

And finally, higher levels of serotonin are associated with greater confidence.

最后，血清素水平越高，越能加强自信。

First, it optimizes the levels of neurotransmitters like serotonin, norepinephrine, and dopamine.

首先，它能优化神经递质水平，如血清素、去甲肾上腺素和多巴胺。

First off, serotonin isn't the only neurotransmitter that plays a role.

首先，5-羟色胺不是唯一起作用的神经递质。

You've probably heard of a couple of these neurotransmitters—serotonin and norepinephrine.

或许你可能听过几种神经递质介质——5-羟色胺与降肾上腺素。

Is it Cortisol, testosterone, insulin or serotonin. You've got three seconds, go!

是皮质醇、睾丸素、胰岛素还是血清素？你有3秒钟时间，开始！

Well, exercise releases an important blend of mood altering hormones including dopamine, serotonin and norepinephrine.

通过锻炼，人体会释放一些重要的情绪调节激素，包括多巴胺、血清素和降肾上腺素。

It contains tryptophan, a chemical in the brain that is used to produce serotonin.

它含有色氨酸，即一种在大脑中用来产生血清素的化物质。

They lose their sensitivity to serotonin and norepinephrine. Which leads to...? Impaired cognitive function.

会失去对5 羟色胺和正肾上腺素的敏感性 那就会引起认知功能受损。

Once it hits your bloodstream, it targets three major neurotransmitters — serotonin, dopamine, and norepinephrine.

一旦它进入你的血液，它就会瞄准三种主要的神经递质——血清素、多巴胺和去甲肾上腺素。

Aside from its positive effects on dopamine, exercise also elevates levels of norepinephrine and serotonin.

除了可以增加多巴胺外，锻炼还能提高体内的去甲肾上腺素以及 5-羟色胺水平。

The other looks at how a brain chemical called serotonin regulates the patience of rats.

而另一个则是研究大脑中的一种叫血清素化物质如何调整老鼠的耐受力。

But that serotonin also makes it easier for the itch signal to be re-triggered again.

但是血清素也使得瘙痒信号更容易再次被触发。

What happens is your serotonin levels are down and melatonin which makes you sleepy, that's up.

于是血清素水平下降，褪黑素上升，让你犯困。