Sievers J, Hartmann D, Pehlemann F W, Berry M
Anatomisches Institut, Universität Kiel, Federal Republic of Germany.
J Comp Neurol. 1992 Jun 1;320(1):1-32. doi: 10.1002/cne.903200102.
The histogenesis of the hamster dentate gyrus was studied with light and electron microscopy and antisera against the astrocyte-associated antigens vimentin and GFAP, in order to follow the differentiation of radial glial cells and astrocytes. The formation of the stratum granulosum is preceded by the establishment of successive dentate matrices, which are formed by cells that leave the ventricular neuroepithelium and occupy positions above the fimbria (suprafimbrial), below the pial surface (subpial), and within the dentate hilus (hilar dentate matrix). The subpial dentate matrix invades the marginal zone of that region of the cerebral wall, where the stratum granulosum will later develop. From the beginning of its existence on embryonal day 13 (E13) up to its disappearance about postnatal day 7 (P7), it is characterized by a high content of GFAP-positive cells and mitoses. This indicates early gliogenesis in the dentate anlage, long before the appearance of the stratum granulosum. Many of the bipolar GFAP-positive cells are oriented parallel to the pial surface and have focal contacts to the pial basement membrane. The establishment of the subpial dentate matrix splits the primordial radial glial scaffold of the hippocampal/dentate anlage into two bundles: 1) the suprafimbrial bundle that retains its original radial position between ventricle and pial surface; and 2) the dorsal glial bundle that traverses the ventral tip of the pyramidal cell layer of future CA3. The latter is pushed dorsolaterally, away from the pial surface, by the enlargement of the subpial dentate matrix and, later, by the suprapyramidal blade. The latter emerges around birth as small radial columns of granule cells located between the bent basal parts of the ventralmost fibers of the dorsal glial bundle and the subpial dentate matrix. From the beginning of its existence it is traversed by unipolar "secondary" radial glial fibers that appear to originate from the subpial dentate matrix. Both the supra- and the infrapyramidal blades seem to elongate by the addition of postmitotic granule cells and "secondary" radial glial cells from the subpial dentate matrix to the growing end of the primordial stratum granulosum. The hilar dentate matrix that is localized in the prospective hilar region, inside the growing stratum granulosum, also contains glial cells that seem to be incorporated into the stratum granulosum. The dentate gyrus is demarcated from the CA1 region of the hippocampus proper by GFAP-positive cells that populate the hippocampal fissure, and that also originate from the subpial dentate matrix.(ABSTRACT TRUNCATED AT 400 WORDS)
为了追踪放射状胶质细胞和星形胶质细胞的分化过程，利用光学显微镜、电子显微镜以及针对星形胶质细胞相关抗原波形蛋白和胶质纤维酸性蛋白（GFAP）的抗血清，对仓鼠齿状回的组织发生进行了研究。颗粒层的形成之前会先后建立齿状基质，这些基质由离开脑室神经上皮并占据海马伞上方（海马伞上）、软膜表面下方（软膜下）以及齿状回门内（门齿状基质）位置的细胞形成。软膜下齿状基质侵入脑壁该区域的边缘区，颗粒层随后将在此处发育。从胚胎第13天（E13）开始存在直至出生后约第7天（P7）消失，其特征是GFAP阳性细胞和有丝分裂的含量很高。这表明在齿状原基中胶质细胞生成较早，远早于颗粒层的出现。许多双极GFAP阳性细胞与软膜表面平行排列，并与软膜基底膜有局部接触。软膜下齿状基质的建立将海马/齿状原基的原始放射状胶质支架分为两束：1）海马伞上束，保留其在脑室和软膜表面之间的原始放射状位置；2）背侧胶质束，穿过未来CA3锥体细胞层的腹侧尖端。后者由于软膜下齿状基质的扩大，以及后来由于锥体上叶片的扩大，被推向背外侧，远离软膜表面。锥体上叶片在出生时以颗粒细胞的小放射状柱出现，位于背侧胶质束最腹侧纤维的弯曲基部和软膜下齿状基质之间。从其开始存在起，就有单极的“次级”放射状胶质纤维穿过，这些纤维似乎起源于软膜下齿状基质。锥体上和锥体下叶片似乎都通过将有丝分裂后的颗粒细胞和来自软膜下齿状基质的“次级”放射状胶质细胞添加到原始颗粒层的生长末端而延长。位于生长中的颗粒层内预期门区的门齿状基质也含有似乎并入颗粒层的胶质细胞。齿状回通过填充海马裂的GFAP阳性细胞与海马体适当的CA1区域区分开来，这些细胞也起源于软膜下齿状基质。（摘要截短于400字）
