Kaslin Jan, Ganz Julia, Brand Michael
Biotechnology Centre and Centre for Regenerative Therapies Dresden, Dresden University of Technology, Tatzberg 47-51, 01307 Dresden, Germany.
Philos Trans R Soc Lond B Biol Sci. 2008 Jan 12;363(1489):101-22. doi: 10.1098/rstb.2006.2015.
Post-embryonic neurogenesis is a fundamental feature of the vertebrate brain. However, the level of adult neurogenesis decreases significantly with phylogeny. In the first part of this review, a comparative analysis of adult neurogenesis and its putative roles in vertebrates are discussed. Adult neurogenesis in mammals is restricted to two telencephalic constitutively active zones. On the contrary, non-mammalian vertebrates display a considerable amount of adult neurogenesis in many brain regions. The phylogenetic differences in adult neurogenesis are poorly understood. However, a common feature of vertebrates (fish, amphibians and reptiles) that display a widespread adult neurogenesis is the substantial post-embryonic brain growth in contrast to birds and mammals. It is probable that the adult neurogenesis in fish, frogs and reptiles is related to the coordinated growth of sensory systems and corresponding sensory brain regions. Likewise, neurons are substantially added to the olfactory bulb in smell-oriented mammals in contrast to more visually oriented primates and songbirds, where much fewer neurons are added to the olfactory bulb. The second part of this review focuses on the differences in brain plasticity and regeneration in vertebrates. Interestingly, several recent studies show that neurogenesis is suppressed in the adult mammalian brain. In mammals, neurogenesis can be induced in the constitutively neurogenic brain regions as well as ectopically in response to injury, disease or experimental manipulations. Furthermore, multipotent progenitor cells can be isolated and differentiated in vitro from several otherwise silent regions of the mammalian brain. This indicates that the potential to recruit or generate neurons in non-neurogenic brain areas is not completely lost in mammals. The level of adult neurogenesis in vertebrates correlates with the capacity to regenerate injury, for example fish and amphibians exhibit the most widespread adult neurogenesis and also the greatest capacity to regenerate central nervous system injuries. Studying these phenomena in non-mammalian vertebrates may greatly increase our understanding of the mechanisms underlying regeneration and adult neurogenesis. Understanding mechanisms that regulate endogenous proliferation and neurogenic permissiveness in the adult brain is of great significance in therapeutical approaches for brain injury and disease.
胚后神经发生是脊椎动物大脑的一个基本特征。然而，随着系统发育，成年神经发生的水平显著下降。在本综述的第一部分，讨论了成年神经发生及其在脊椎动物中假定作用的比较分析。哺乳动物中的成年神经发生局限于两个端脑组成性活跃区。相反，非哺乳动物脊椎动物在许多脑区表现出大量的成年神经发生。成年神经发生的系统发育差异尚不清楚。然而，表现出广泛成年神经发生的脊椎动物（鱼类、两栖类和爬行类）的一个共同特征是与鸟类和哺乳动物相比，胚后脑有大量生长。鱼类、青蛙和爬行类的成年神经发生可能与感觉系统和相应感觉脑区的协调生长有关。同样，与更依赖视觉的灵长类动物和鸣禽相比，以嗅觉为主的哺乳动物的嗅球会大量增加神经元，而灵长类动物和鸣禽的嗅球增加的神经元则少得多。本综述的第二部分重点关注脊椎动物大脑可塑性和再生的差异。有趣的是，最近的几项研究表明成年哺乳动物大脑中的神经发生受到抑制。在哺乳动物中，神经发生可在组成性神经发生的脑区诱导，也可在损伤、疾病或实验操作后异位诱导。此外，多能祖细胞可从哺乳动物大脑的几个原本静止的区域体外分离和分化。这表明在非神经发生脑区募集或产生神经元的潜力在哺乳动物中并未完全丧失。脊椎动物成年神经发生的水平与损伤再生能力相关，例如鱼类和两栖类表现出最广泛的成年神经发生，也具有最大的中枢神经系统损伤再生能力。在非哺乳动物脊椎动物中研究这些现象可能会极大地增进我们对再生和成年神经发生潜在机制的理解。了解调节成年大脑内源性增殖和神经发生许可的机制对脑损伤和疾病的治疗方法具有重要意义。
