Morriss G M, Solursh M
J Embryol Exp Morphol. 1978 Aug;46:37-52.
Rat embryos with two to four pairs of somites (day 9 of gestation) were examined by scanning electron microscopy and Alcian blue staining. The neural folds, which represent only future brain region at this stage, form a pair of elongated hemispheres with a deep neural groove between them. In transverse section the neural ectoderm is biconvex; the cranial mesenchyme cells beneath them are widely separated by extracellular matrix (ECM) and are joined to each other and to the ectodermal basement membrane by fine cytoplasmic processes and strands of ECM material. In contrast, mesenchyme cells close to the primitive streak are closely packed, having broad areas of surface contact and only small amounts of ECM. The nature and distribution of ECM, cell surface, and basement membrane glycosaminoglycans (GAG) were investigated by staining with Alcian blue at specific pH values in combination with enzyme pretreatments, and at various critical electrolyte concentrations. The results indicate that the GAG of the ectodermal basement membrane, mesenchymal ECM and mesenchymal cell surfaces are in continuity with each other and consist largely of hyaluronate and chondroitin sulphates. Differences in morphology and histochemistry of neural fold and primitive streak regions are discussed in relation to their possible morphogenetic significance.
采用扫描电子显微镜和阿尔新蓝染色法对妊娠第9天有2至4对体节的大鼠胚胎进行了检查。神经褶在这个阶段仅代表未来的脑区，形成一对细长的半球，它们之间有一条深的神经沟。在横切面上，神经外胚层是双凸的；其下方的颅间充质细胞被细胞外基质（ECM）广泛分隔，并通过细的细胞质突起和ECM物质链相互连接并与外胚层基底膜相连。相比之下，靠近原条的间充质细胞紧密堆积，具有广泛的表面接触区域且只有少量的ECM。通过在特定pH值下结合酶预处理以及在各种临界电解质浓度下用阿尔新蓝染色，研究了ECM、细胞表面和基底膜糖胺聚糖（GAG）的性质和分布。结果表明，外胚层基底膜、间充质ECM和间充质细胞表面的GAG相互连续，主要由透明质酸和硫酸软骨素组成。讨论了神经褶和原条区域在形态学和组织化学上的差异与其可能的形态发生意义。
