人胎初级视皮质含Calbindin神经元的发育

本文采用免疫细胞化学方法研究了16～38周人胎儿初级树皮质含Calbindin神经元的发育．16周时,含Calbindin神经元主要分布于脑室带、脑室下带和中间带深部,其他皮质带散在存在。脑室带和脑室下带的细胞大多跑体较大,胞浆和胞核均含阳性产物,而其它皮质带细胞胞核常不染色。19周时,脑室带和脑室下带的含Cal－bindin神经元明显减少,仅存在极少量,其它皮质带含Calbindin神经元的状况类似16周。21周时大多数含Cal－bindin神经元位于Ⅴ、Ⅵ层。以后,随着服龄增大,较多的含Calbindin神经元逐渐依次出现于Ⅳ、Ⅲ和Ⅱ层,遵循皮质神经元从深至浅的发育规律。这些神经元的形态也由以双极细胞为主发育成以多极细胞为主,染色逐渐加深,突起逐渐增长。在19～28周,皮质Ⅰ层的一些Cajal-Retzius细胞和水平纤维亦表达Calbindin。本实验中较多的含Calbindin神经元于发育早期在皮质增殖带的出现,提示Calbindin在皮质的早期发育过程中可能发挥重要作用。

DEVELOPMENT OF CALBINDIN-CONTAINING NEURONS IN THE PRIMARY VISUAL CORTEX OF HUMAN FETUS

Development of calbindin-containing neurons in the primary visual cortex of human fetuses aged from 16 weeks to 38 weeks was investigated immunocytochemically. At 16 weeks, calbindin-containing neurons were mainly localized in ven-tricular zone (VZ), subventricular zone (SVZ) and deep patt of intermediate zone (IZ) ,and a little scattered in other corti-cal zones. Cell bodies of calbindin-containing neurons in VZ and SVZ were relatively large and contained positive products in both plasma and nucleus;the nucleus of calbindin-containing neurons in other cortical zones was usually negative. At 19 weeks, the number of calbindin-containing neurons in VZ and SVZ was markedly decreaSed, only a few were observed. At 21 weeks, most calbindin-containing neurons were concentrated in layer V and VI. As the age increased, more and more cal-bindin-containing neurons appeared gradually in superficial layers, in sequence of IV, III and II, following the oinside-out"rule of development of cortical neurons. The proportion of bipolar and multipolar calbindin-containing neurons also changed with ages. Much more bipolar calbindin-containing neurons than multipolar ones were found in young ages. In older ages,much more multipolar calbindin-containing neurons than bipolar ones were observed. The staining intensity of calbindin-con-taining neurons increased with the advance of the ages. At 19~28 weeks, part of Cajal-Retiius cells and horizontal fibers in deep layer I also contained calbindin, and few calbindin-containing pyramidal neurons were observed. The early appearance of calbindin-containing neurons in active proliferation zones (VZ, SVZ) suggest that calbindin may play an important role in early development of the cerebral cortex.