Uniquely hominid features of adult human astrocytes.
Uniquely hominid features of adult human astrocytes.
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DOI：
10.1523/jneurosci.4707-08.2009
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发表时间：
2009-03-11
期刊：
影响因子：
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通讯作者：
Nedergaard M
中科院分区：
文献类型：
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作者：
Oberheim NA;Takano T;Han X;He W;Lin JH;Wang F;Xu Q;Wyatt JD;Pilcher W;Ojemann JG;Ransom BR;Goldman SA;Nedergaard M
定义人类大脑和其他哺乳动物大脑之间的微观解剖差异是理解其独特计算能力的关键。虽然很多努力都致力于神经元的比较研究，星形胶质细胞受到的关注要少得多。我们在这里报告说，人类新皮层的原生质星形胶质细胞的直径是2.6倍，并延长10倍以上的GFAP+初级过程比他们的啮齿类动物。在从急性切除的手术组织制备的皮质切片中，原生质星形胶质细胞以36 µm/s的速度传播Ca 2+波，大约比啮齿动物快4倍。人星形胶质细胞也瞬时增加胞浆Ca 2+在响应于谷氨酸能和嘌呤能受体激动剂。人类新皮质还含有几种解剖学定义的星形胶质细胞亚类，在啮齿动物中不存在。这些包括位于第5-6层的星形胶质细胞群，并延伸长纤维，其特征在于规则间隔的静脉曲张。另一种特殊类型的星形胶质细胞，层间星形胶质细胞，丰富地填充表层皮质层，并将长突起延伸到皮质层3和4。人类纤维状星形胶质细胞类似于啮齿类动物，但直径更大。因此，人类皮质星形胶质细胞比啮齿类动物更大，结构更复杂，更多样化。在此基础上，我们认为这种星形胶质细胞的复杂性使成年人大脑的功能能力增加。
Defining the microanatomic differences between the human brain and that of other mammals is key to understanding its unique computational power. While much effort has been devoted to comparative studies of neurons, astrocytes have received far less attention. We report here that protoplasmic astrocytes in human neocortex are 2.6 fold larger in diameter and extend 10-fold more GFAP+ primary processes than their rodent counterparts. In cortical slices prepared from acutely resected surgical tissue, protoplasmic astrocytes propagate Ca2+ waves with a speed of 36 µm/second, approximately 4-fold faster than rodent. Human astrocytes also transiently increase cystosolic Ca2+ in response to glutamatergic and purinergic receptor agonists. The human neocortex also harbors several anatomically-defined subclasses of astrocytes not represented in rodents. These include a population of astrocytes that reside in layers 5–6 and extend long fibers characterized by regularly spaced varicosities. Another specialized type of astrocyte, the interlaminar astrocyte, abundantly populates the superficial cortical layers and extends long processes without varicosities to cortical layers 3 and 4. Human fibrous astrocytes resemble their rodent counterpart, but are larger in diameter. Thus, human cortical astrocytes are both larger, and structurally both more complex and more diverse, than those of rodents. On this basis, we posit that this astrocytic complexity has permitted the increased functional competence of the adult human brain.