据美国生物学新闻网12月26日报道，美国约翰-霍普金斯大学细胞工程学院的科学家近日发现了新神经元细胞整合到大脑现有系统的过程。
一个多世纪以来，科学家一直认为成人大脑只会失去神经细胞，而不会获得新的细胞。然而，美科学研究显示包括人在内的所有成年动物的大脑都会制造新的神经细胞，并且可以成为成人大脑系统的一个工作部分。在对新神经元细胞如何进入大脑现有系统的第一次研究中，约翰-霍普金斯大学的研究人员发现，一种名为伽马氨基丁酸的大脑化学物质发挥了重要作用。
在成人大脑中，谷氨酸盐通常被认为是最具有刺激性的化学物质，伽马氨基丁酸则是主要的抑制化学物质。但是，研究人员这次发现，新的神经细胞由伽马氨基丁酸进行刺激，不管是在胎儿大脑还是成人大脑中。研究人员称，整合过程本质上就是将神经细胞从成长中的细胞转变成一个成熟神经细胞，最初它由伽马氨基丁酸进行刺激，但当完全整合时，新的神经细胞将与其它成熟细胞一样对伽马氨基丁酸和谷氨酸盐做出反应。
美国研究人员的这个发现将有助于增加大脑神经元细胞再生的研究工作，即研究如何使移植的干细胞更好地与其它细胞连接。这项发现发布在12月的《自然》杂志期刊上。
英文：
In experiments with mice, scientists from Johns Hopkins' Institute for Cell Engineering have discovered the steps required to integrate new neurons into the brain's existing operations.
For more than a century, scientists thought the adult brain could only lose nerve cells, not gain them, but in fact, new neurons do form during adulthood in all mammals, including humans, and become a working part of the adult brain in mice at the very least.
In the first study to show how these "baby" neurons are integrated into the brain's existing networks, the Johns Hopkins researchers show that a brain chemical called GABA readies baby neurons to make connections to old ones. The discovery is described in the Dec. 11 advance online section of Nature.
"GABA is important during fetal development, but most scientists thought it would have the same role it has with adult neurons, which is to inhibit the cells' signals," says Hongjun Song, Ph.D., an assistant professor in the Neuroregeneration and Repair Program within ICE. "We've shown that GABA instead excites new neurons and that this is the first step toward their integration into the adult brain |
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