Vigh B, Vigh-Teichmann I
2nd Department of Anatomy, Histology and Embryology, Semmelweis University Medical School, Budapest, Hungary.
Arch Histol Cytol. 1989;52 Suppl:433-40. doi: 10.1679/aohc.52.suppl_433.
The pinealocytes--the main cellular elements of the pineal organ--are polarized, displaying a (photo)receptor and an axonic effector cell pole. The receptor endings are of two main types: they bear rod-type or cone-type outer segments characterized by the presence of immunoreactive opsin-, S-antigen- and vitamin A-binding sites. The effector pole may form ribbon-containing synapses on the secondary pineal neurons, and/or neurohormonal terminals on the basal lamina of the pineal nervous tissue. Applying potassium pyroantimonate (PPA) to electron-microscopic histochemistry, we found in the frog that both effector terminals and photoreceptor outer segments contained a large amount of Ca-pyroantimonate deposit similar to retinal cones and rods. Rods and rod-like pinealocytes contained more deposits than cones. The higher concentration of calcium on the cell membranes of dark pinealocytes in the rat may be connected with their rod-like character. In the frog, a high amount of calcium seemed to be concentrated in the photoreceptor effector terminals, especially around their synaptic ribbons, and in myeloid bodies of the pineal ependyma and retinal pigment epithelium. Calcium was richly found in or around corpora arenacea in the human and rat pineal. It is suggested that the formation of concrements may be connected with the high demand of Ca-exchange of pinealocytes for their receptor and effector membrane functions. In the rat, lymphocytes were found to migrate through the wall of the vena magna of Galen and to closely contact pinealocytes, presumably to receive immunological information as an additional pineal output.
松果体细胞——松果体器官的主要细胞成分——是极化的，呈现出一个（光）感受器和一个轴突效应器细胞极。感受器末梢主要有两种类型：它们带有杆状或锥状外段，其特征是存在免疫反应性视蛋白、S抗原和维生素A结合位点。效应器极可能在次级松果体神经元上形成含带状突触，和/或在松果体神经组织基膜上形成神经激素终末。通过将焦锑酸钾（PPA）应用于电子显微镜组织化学，我们在青蛙中发现，效应器终末和光感受器外段都含有大量类似于视网膜视锥和视杆的焦锑酸钙沉积物。视杆和杆状松果体细胞比视锥含有更多的沉积物。大鼠暗松果体细胞细胞膜上较高的钙浓度可能与其杆状特征有关。在青蛙中，大量的钙似乎集中在光感受器效应器终末，尤其是在其突触带周围，以及松果体室管膜和视网膜色素上皮的髓样小体中。在人类和大鼠松果体的脑砂内或其周围富含钙。有人认为，脑砂的形成可能与松果体细胞对其感受器和效应器膜功能的高钙交换需求有关。在大鼠中，发现淋巴细胞穿过大脑大静脉壁并与松果体细胞紧密接触，推测是为了接收作为松果体额外输出的免疫信息。
