Novier A, Nicolas D, Krstic R
Institut d'Histologie et d'Embryologie, Faculté de Médicine, Université de Lausanne, Switzerland.
J Pineal Res. 1996 Oct;21(3):121-30. doi: 10.1111/j.1600-079x.1996.tb00279.x.
Calretinin (CR) is a calcium-binding protein, found in a variety of organs and systems such as the central nervous system and the pineal gland. It was first thought to be a specific neuronal marker but this selectivity is now in question since CR has been demonstrated in avian thymus, rat ovary, rat and guinea pig inner ear, rat testis, and chicken and rat pineal gland. To contribute to the knowledge of the presence of CR-positive cells in the pineal parenchyma of rat and other mammalian including man, we performed immunocytochemistry on pineal glands of gerbils, rats, goats, cows, and humans, using a CR anti-serum. To confirm it was actually CR that was demonstrated, we performed Western Blot analyses. Finally, to precisely identify the nature of CR-positive cells we accomplished double-labelling immunofluorescence, using antisera against some nerve cell specific cytosquelettal proteins such as MAP-5, MAP-2, NF-L, NF-M, and NF-H. CR-positive cells were found in all pineal glands studied. These cells all possess a round, oval, or polygonal-shaped perikaryon sending one or more processes of different lengths into the glandular parenchyma. There is a lack of CR immunoreactivity in the nucleus and cell organelles while the cytosol contains a high concentration of this protein. Nevertheless, there are some slight differences between species, especially concerning the number of reactive cells and their relationships with different parenchymal structures such as blood vessels or acervuli. Among the CR-positive cells, only a few were actually nerve cells, contributing probably to an intrinsic innervation of the gland. The remaining CR-reactive cells seem to correspond mostly to pinealocytes in a specific histophysiological state and possibly to neuron-like cells. The significance of the CR-positive cells in the pineal glands remains to be elucidated.
钙视网膜蛋白（CR）是一种钙结合蛋白，存在于多种器官和系统中，如中枢神经系统和松果体。它最初被认为是一种特异性神经元标志物，但由于CR已在禽胸腺、大鼠卵巢、大鼠和豚鼠内耳、大鼠睾丸以及鸡和大鼠松果体中被证实存在，这种选择性现在受到质疑。为了增进对大鼠以及包括人类在内的其他哺乳动物松果体实质中CR阳性细胞存在情况的了解，我们使用CR抗血清对沙鼠、大鼠、山羊、牛和人类的松果体进行了免疫细胞化学研究。为了证实所显示的确实是CR，我们进行了蛋白质免疫印迹分析。最后，为了精确确定CR阳性细胞的性质，我们使用针对一些神经细胞特异性细胞骨架蛋白（如MAP - 5、MAP - 2、NF - L、NF - M和NF - H）的抗血清完成了双标记免疫荧光实验。在所研究的所有松果体中均发现了CR阳性细胞。这些细胞均具有圆形、椭圆形或多边形的核周体，向腺实质发出一个或多个不同长度的突起。细胞核和细胞器中缺乏CR免疫反应性，而细胞质中含有高浓度的这种蛋白质。然而，不同物种之间存在一些细微差异，特别是在反应性细胞的数量以及它们与不同实质结构（如血管或凝块）的关系方面。在CR阳性细胞中，实际上只有少数是神经细胞，可能对腺体的内在神经支配有贡献。其余的CR反应性细胞似乎大多对应于处于特定组织生理状态的松果体细胞，也可能对应于神经元样细胞。松果体中CR阳性细胞的意义仍有待阐明。
