Ohshima K, Matsuo S
Laboratory of Functional Anatomy, Faculty of Agriculture, Shinshu University, Nagano-ken, Japan.
J Pineal Res. 1988;5(4):397-410. doi: 10.1111/j.1600-079x.1988.tb00888.x.
Cytodifferentiation of the chick pineal gland throughout the embryonic development was investigated with light and electron microscopy. The chick pineal anlage appears first as a small evagination in the diencephalic roof at 60 h of incubation (27-30 somites). Until day 5 of incubation, pineal anlage cells are undifferentiated and appear similar to ventricular ependymal cells. Subsequently, pinealocytes and supporting cells are first distinguishable at 7-8 days, and parafollicular cells are distinguishable at 12 days of incubation. Pigment-containing cells after 6 days and nerve cells after 17 days of incubation gradually increase, especially in the posterior wall of the pineal recess. During embryonic development, the chick pineal gland has both photosensory and secretory elements: viz. the former, mitochondria-laden apical protrusions, synaptic ribbons, lamellar whorl-like cilia of the pinealocytes, and adjacent appearance of the pigment-containing cells and the nerve cells; and the latter, dense-cored vesicles of the pinealocytes and dense bodies of the supporting cells. Moreover, nuclear invaginations having a large lipid droplet nearby and some aggregations of glycogen are found in the pinealocytes and are transitory changes in structure restricted to certain days of incubation.
利用光学显微镜和电子显微镜对鸡胚发育过程中松果体的细胞分化进行了研究。鸡松果体原基最初在孵化60小时（27 - 30体节）时，表现为间脑顶部的一个小突起。在孵化第5天之前，松果体原基细胞未分化，与脑室室管膜细胞相似。随后，松果体细胞和支持细胞在7 - 8天首次可区分，滤泡旁细胞在孵化12天时可区分。孵化6天后含色素细胞和17天后神经细胞逐渐增多，尤其在松果体隐窝后壁。在胚胎发育过程中，鸡松果体具有感光和分泌两种成分：前者，松果体细胞富含线粒体的顶端突起、突触带、板层状螺旋状纤毛，以及含色素细胞和神经细胞的相邻出现；后者，松果体细胞的致密核心小泡和支持细胞的致密体。此外，在松果体细胞中发现有附近有大脂滴的核内陷以及一些糖原聚集，这些是仅限于特定孵化天数的结构短暂变化。
