科学家发现让大脑清醒的物质

 　　LONDON, July 29 (Xinhua) -- By changing some particular brain chemicals lab mice would become hyperactive and sleep for just 65 percent of their normal time, according to a study released Wednesday by the Imperial College London.

　　The chemicals, histamine and GABA, are produced in a primitive¹ part of the brain that is highly similar in mice and humans.

　　Scientists already know the chemical histamine sends signals to the brain to make it awake. The new research suggests that the chemical GABA acts against histamine, like a chemical "brake" preventing wakefulness being too intense.

　　Researchers discover brain chemicals affecting wakefulness

　　Researchers from the Imperial College London altered the levels of the GABA produced by the mice's brains and measured what changes this had on their brain activity over the day and night.

　　They found that compared with normal mice, those without GABA ran twice as far and twice as fast, and maintained or even increased their overall activity over a 30 minute period.

　　The affected² mice also stayed awake much longer in the day, and when they did sleep, the mice experienced just 65 per cent of normal sleep.

　　"Wakefulness stimulated³ by histamine may be too much of a good thing, and so the brain has a built in brake on histamine's wake-inducing actions," said Stephen Brickley, who participated in the study.

　　This discovery could help researchers to develop new drugs that promote better sleep, or control hyperactivity in people with the medical condition mania⁴, according to the study published in the journal Neuron.

1 primitive   

adj.原始的；简单的；n.原(始)人，原始事物

参考例句：

• It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
• His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。

2 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

3 stimulated   

a.刺激的

参考例句：

• The exhibition has stimulated interest in her work. 展览增进了人们对她作品的兴趣。
• The award has stimulated her into working still harder. 奖金促使她更加努力地工作。

4 mania   

n.疯狂；躁狂症，狂热，癖好

参考例句：

• Football mania is sweeping the country.足球热正风靡全国。
• Collecting small items can easily become a mania.收藏零星物品往往容易变成一种癖好。