(单词翻译:单击)
Scientists have for the first time determined1 the three-dimensional atomic structure of a human opioid(阿片样物质) receptor, a molecule2 on the surface of brain cells that binds3 to opioids and is centrally involved in pleasure, pain, addiction4, depression, psychosis, and related conditions. Dozens of legal and illegal drugs, from heroin5 to hospital anesthetics(麻醉药) , work by targeting these receptors. The detailed6 atomic structure information paves the way for the design of safer and more effective opioid drugs. "This finding is going to have a major impact on understanding the fundamental principles of opioid receptor recognition and evolution," said Raymond Stevens, PhD, a professor at The Scripps Research Institute. Stevens is the senior author of the new study, which appears online in the journal Nature on March 21, 2012.
A Symphony of Activity
Opioid receptor subtypes in the human brain work together in a symphony of activity that is still not fully7 understood. The "mu" opioid receptors mediate8 feelings of pleasure and pain-relief; they are the prime targets of the body's own endorphin neurotransmitters as well as heroin, morphine(吗啡) , and most other opioid drugs. By contrast, "kappa" opioid receptors are bound by neurotransmitters known as dynorphins, and when activated9 can depress mood and produce dissociative, psychedelic(迷幻剂) experiences. The plant Salvia divinorum, which was originally cultivated by Mesoamerican societies for religious ceremonies and is now used widely as a recreational drug, has an active ingredient, Salvinorin A, that binds selectively and with high affinity10 to kappa opioid receptors.
"We don't know why kappa receptors evolved, but we know that they have been around for a long time in evolutionary11 terms; even frogs have them," said Bryan Roth, a professor of pharmacology and an opioid receptor expert at the University of North Carolina, whose group teamed with the Stevens lab for the new study.
If their psychedelic and mood-darkening effects could be avoided somehow, kappa opioid receptor activators, or "agonists," could be very useful medically. In animal studies, they act as mild and non-addicting pain-relievers, weaken the addictive12 effects of other drugs, and reduce irritable13 bowel14 signs. "Antagonist15" compounds that block kappa opioid receptor activity also show promise as treatments for depression, anxiety, and other psychiatric conditions. Even the psychedelic effects associated with kappa receptor activation16 could be useful in providing insights into perception and consciousness. "This is a receptor that is important for how we see reality," said Roth.
1
determined
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adj.坚定的;有决心的 | |
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2
molecule
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n.分子,克分子 | |
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3
binds
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v.约束( bind的第三人称单数 );装订;捆绑;(用长布条)缠绕 | |
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4
addiction
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n.上瘾入迷,嗜好 | |
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5
heroin
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n.海洛因 | |
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6
detailed
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adj.详细的,详尽的,极注意细节的,完全的 | |
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7
fully
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adv.完全地,全部地,彻底地;充分地 | |
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8
mediate
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vi.调解,斡旋;vt.经调解解决;经斡旋促成 | |
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9
activated
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adj. 激活的 动词activate的过去式和过去分词 | |
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10
affinity
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n.亲和力,密切关系 | |
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11
evolutionary
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adj.进化的;演化的,演变的;[生]进化论的 | |
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12
addictive
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adj.(吸毒等)使成瘾的,成为习惯的 | |
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13
irritable
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adj.急躁的;过敏的;易怒的 | |
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14
bowel
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n.肠(尤指人肠);内部,深处 | |
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15
antagonist
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n.敌人,对抗者,对手 | |
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16
activation
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n. 激活,催化作用 | |
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