科学家发现记忆的一个秘密
(家庭医生医疗保健网雅文报导)路透社纽约健康消息-美国普林斯顿大学研究人员发现记忆的一个秘密：NMDA受体在将短期记忆转换为长期记忆的过程中起关键作用。多年来，科学家一直在探讨人生经历中的特定时刻是怎样进入大脑的记忆库中去的。根据这个发现，研究人员认为，可能是脑内的受体使过去的生活经历保存在脑中。
用小鼠所做的研究表明，这些被称为NMDA(针对N-甲基-D-天冬氨酸)的受体，似乎在将短期记忆转换为长期记忆的过程中起关键作用，这一过程是记忆的巩固过程。
据研究员介绍：NMDA受体是某些类型的学习过程所必需的，但是它在记忆巩固中所起的作用(此过程需数日到数周)，在此之前还未做过详细的研究。
为探讨NMDA在记忆形成中所起的作用，研究者使用遗传技术培育出含有NMDA受体的大鼠，可通过喂不同的食物来控制其体内NMDA受体的开放与关闭。多种测试显示，当这些大鼠的NMDA受体开放时，它们学习得像正常老鼠一样好；而受体关闭时学习效果削弱了。在实验中，当NMDA受体被打开之后，老鼠们忙于学习任务，如果受体继续保持开放，他们会记得那些任务；但是如果在学习这项任务以后关掉受体，老鼠就忘记他们学过的东西。
, 百拇医药
研究员最后得出结论：记忆的加强分为若干周期，通过这些周期确定什么样的学习内容要作为长期记忆保存，每个周期均需要NMDA受体。关闭 NMDA 受体会使复杂记忆(如记忆特殊情况下的反应)明显削弱。
来源：《科学》2000;290:1170-1174
Memories Are Made of This
NEW YORK (Reuters Health) - From a lifetime of experience, how do specific moments make their way into the mind‘s album of memories? The answer, according to researchers, may lie in brain receptors that work to keep the past alive.
, 百拇医药
These receptors, called NMDA (for N-methyl-D-aspartate), appear to play a key role in turning those short-term recollections into long-term memories--a process known as memory consolidation--according to results of studies in mice.
The NMDA receptor is required for certain types of learning, but its role in memory consolidation--which takes days to weeks to develop--has not been studied in detail before now, according to Eiji Shimizu and associates from Princeton University in New Jersey.
, http://www.100md.com
To sort out the role of NMDA in memory formation, the investigators used genetic techniques to breed rats that contained NMDA receptors that could be turned on or off depending on what the rats were fed.
In a variety of tests, learning was impaired in rats while their NMDA receptors were turned off, though they learned just as well as normal rats when their receptors were turned on, the authors report.
Rats that engaged in learning tasks while their NMDA receptors were turned on later remembered those tasks if their receptors were kept on, the researchers note, but if their receptors were turned off after the task was learned, the rats forgot what they had learned.
, http://www.100md.com
Complex memories--remembering how to react in a particular situation, for example--were especially impaired by turning off the NMDA receptors, according to the report in the November 10th issue of Science.
Based on their results, Shimizu and colleagues conclude that several rounds of memory reinforcement--each round requiring the NMDA receptor--are needed to be certain that what is learned is retained as long-term memory.
SOURCE: Science 2000;290:1170-1174., http://www.100md.com
用小鼠所做的研究表明，这些被称为NMDA(针对N-甲基-D-天冬氨酸)的受体，似乎在将短期记忆转换为长期记忆的过程中起关键作用，这一过程是记忆的巩固过程。
据研究员介绍：NMDA受体是某些类型的学习过程所必需的，但是它在记忆巩固中所起的作用(此过程需数日到数周)，在此之前还未做过详细的研究。
为探讨NMDA在记忆形成中所起的作用，研究者使用遗传技术培育出含有NMDA受体的大鼠，可通过喂不同的食物来控制其体内NMDA受体的开放与关闭。多种测试显示，当这些大鼠的NMDA受体开放时，它们学习得像正常老鼠一样好；而受体关闭时学习效果削弱了。在实验中，当NMDA受体被打开之后，老鼠们忙于学习任务，如果受体继续保持开放，他们会记得那些任务；但是如果在学习这项任务以后关掉受体，老鼠就忘记他们学过的东西。
, 百拇医药
研究员最后得出结论：记忆的加强分为若干周期，通过这些周期确定什么样的学习内容要作为长期记忆保存，每个周期均需要NMDA受体。关闭 NMDA 受体会使复杂记忆(如记忆特殊情况下的反应)明显削弱。
来源：《科学》2000;290:1170-1174
Memories Are Made of This
NEW YORK (Reuters Health) - From a lifetime of experience, how do specific moments make their way into the mind‘s album of memories? The answer, according to researchers, may lie in brain receptors that work to keep the past alive.
, 百拇医药
These receptors, called NMDA (for N-methyl-D-aspartate), appear to play a key role in turning those short-term recollections into long-term memories--a process known as memory consolidation--according to results of studies in mice.
The NMDA receptor is required for certain types of learning, but its role in memory consolidation--which takes days to weeks to develop--has not been studied in detail before now, according to Eiji Shimizu and associates from Princeton University in New Jersey.
, http://www.100md.com
To sort out the role of NMDA in memory formation, the investigators used genetic techniques to breed rats that contained NMDA receptors that could be turned on or off depending on what the rats were fed.
In a variety of tests, learning was impaired in rats while their NMDA receptors were turned off, though they learned just as well as normal rats when their receptors were turned on, the authors report.
Rats that engaged in learning tasks while their NMDA receptors were turned on later remembered those tasks if their receptors were kept on, the researchers note, but if their receptors were turned off after the task was learned, the rats forgot what they had learned.
, http://www.100md.com
Complex memories--remembering how to react in a particular situation, for example--were especially impaired by turning off the NMDA receptors, according to the report in the November 10th issue of Science.
Based on their results, Shimizu and colleagues conclude that several rounds of memory reinforcement--each round requiring the NMDA receptor--are needed to be certain that what is learned is retained as long-term memory.
SOURCE: Science 2000;290:1170-1174., http://www.100md.com