加载中…眼睛细胞可能是研制更好睡眠药的关键（中英参照）
(2008-10-25 02:57:10)
标签：
英语中英参照睡眠亚健康眼睛催眠药视网膜节细胞健康 |
分类： 健康保健 |
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在老鼠上的实验表明，睡眠可以被眼睛的一组神经细胞所控制。英国的科学家周日宣布，这个发现为制造更好的睡眠药研发提供了新的目标。
光线的水平可影响清醒程度早已为人所知，这就是为什么光线暗弱的房间令人昏昏欲睡。但其生物学机理尚不清楚。
目前，牛津大学研究者已经发现了一些叫做视网膜节细胞（Retinal ganglion cells）对睡眠可能起到重要作用。一般来说，老鼠的这些细胞被关闭时，光线对其睡眠和清醒的作用将完全不起作用。
Nuffield 眼科实验室的研究牵头人Russell Foster 认为，“我们对调节睡眠和醒来发现了一条新的通道。”“如果我们能在药理学上模仿成这种光线的效果，我们就可以随心所欲地控制睡眠。”
现已发明有许多药物用于调节睡眠—清醒循环，营造了每年数十亿美元的催眠药市场。但目前这类的药物的作用尚不成熟，副作用较多。
当将研究视线转移到控制视网膜节细胞的特殊机制时，就可能在将来发展出精良的治疗药物。
研究者已能够追踪通往大脑的睡眠通道，发现有两个诱导睡眠的中心可以直接被这种眼细胞活跃化。
然而，研究仍处早期阶段，科学家尚不清楚这种影响老鼠睡眠的过程是否有效于人类。因为老鼠是夜行动物，在该动物身上的实验效果可能与人类预期的机制正好相反。老鼠通常昼伏夜行，当老鼠眼上的这种光线敏感细胞被关闭时，如果光线存在，老鼠会非常清醒。
牛津大学研究组的发现登载在《自然神经科学杂志》上。
Eye cells may hold key to better sleeping pill
Sun Aug 17, 2008 1:07pm EDT
LONDON (Reuters) - Sleepiness can be controlled by a set of nerve cells in the eye, tests on mice suggest, offering a new target for drug developers that may lead to better sleeping pills, British scientists said on Sunday.
Light levels have long been known to affect alertness, which is why dimly lit rooms lead people to feel drowsy. But the biological mechanism for this has been unclear.
Now University of Oxford researchers have discovered that so-called retinal ganglion cells play a key role. In mice where these cells are turned off genetically, the effects of light on sleep and alertness is completely abolished.
"We have discovered a new pathway that modulates sleep and arousal," lead researcher Russell Foster, of the Nuffield Laboratory of Ophthalmology, said.
"If we can mimic the effect of light pharmacologically, we could turn sleep on and off."
Many drugs have been developed to modify sleep-wake cycles, creating a multibillion-a-year sleeping pill market. But the action of current medicines is relatively crude and the drugs have side-effects.
By targeting the specific mechanism controlling the action of retinal ganglion cells, it may be possible in the future to develop much more sophisticated treatments.
The researchers were able to track the sleep pathway to the brain, showing that two sleep-inducing centers there were directly activated by the cells.
The research, however, is still at an early stage and scientists have yet to establish if the same processes affecting the back-to-front world of the mouse will work in humans.
Because mice are nocturnal, the affects seen in the animal tests were opposite to those that would be expected in humans.
Mice normally sleep when it is light and wake up in the dark -- but those mice in which the light-sensitive cells were turned off stayed wide awake when the lights were on.
The Oxford group's findings were published in the journal Nature Neuroscience.
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