Chen Y L, Chen W P, Huang B N, Lin H S
Department of Anatomy, College of Medicine, National Taiwan University, Taipei.
Arch Histol Cytol. 1994 May;57(2):175-86. doi: 10.1679/aohc.57.175.
The pineal organ of the golden hamster consists of deep and superficial portions which are connected to each other by a stalk. The permeability of capillaries for horseradish peroxidase (HRP) injected intravenously was examined in sections of entire portions of the gland that cut either along coronal or sagittal planes. Two distinct portions of the parenchyma, i.e., dorsal major and ventral minor ones, were found in the superficial gland. Most of the capillaries in the dorsal portion were of the continuous type of endothelium, whereas those in the ventral portion were fenestrated. In the dorsal portion, HRP readily crossed the endothelium, permeated the basal lamina, flowed into the perivascular connective tissue space and intruded into the intercellular clefts of the parenchyma. In contrast, HRP was not found to penetrate through the endothelium of the capillaries in the ventral portion to reach the perivascular area, thereby leaving the intercellular clefts of the parenchyma free of HRP. In the deep gland the capillaries were exclusively of the nonfenestrated type. Intravenously injected HRP was prevented from crossing the endothelium by the tight junction. In some areas, HRP penetrated through the capillaries in the pia mater, and crossed the outer limiting membrane to reach the intercellular clefts of the parenchyma and the basal lamina of the capillaries in the peripheral region of the deep pineal gland. The junctions between endothelial cells were not penetrated by HRP. The observations indicate that the type of capillary, absence of perivascular spaces, and permeability in the deep pineal are all similar to these factors in the general brain tissue; they differ from these in the superficial pineal gland, in which the dorsal portion shows characteristics found in other endocrine glands, but the ventral zone exhibits a unique situations: the presence of a blood-pineal barrier with a pericapillary connective tissue area.
金黄仓鼠的松果体器官由深部和浅部组成，二者通过一个柄相连。在沿冠状面或矢状面切开的整个腺体部分的切片中，检查了静脉注射辣根过氧化物酶（HRP）后毛细血管的通透性。在浅部腺体中发现了实质的两个不同部分，即背侧的主要部分和腹侧的次要部分。背侧部分的大多数毛细血管内皮为连续型，而腹侧部分的毛细血管为有孔型。在背侧部分，HRP很容易穿过内皮，渗透到基膜，流入血管周结缔组织间隙并侵入实质的细胞间裂隙。相比之下，未发现HRP穿透腹侧部分毛细血管的内皮到达血管周区域，因此实质的细胞间裂隙中没有HRP。在深部腺体中，毛细血管完全是非有孔型。静脉注射的HRP因紧密连接而无法穿过内皮。在某些区域，HRP穿透软脑膜中的毛细血管，穿过外界膜到达深部松果体周边区域实质的细胞间裂隙和毛细血管的基膜。HRP未穿透内皮细胞之间的连接。这些观察结果表明，深部松果体的毛细血管类型、血管周间隙的缺乏和通透性与一般脑组织中的这些因素都相似；它们与浅部松果体不同，在浅部松果体中，背侧部分表现出其他内分泌腺的特征，但腹侧区域呈现出独特的情况：存在带有血管周结缔组织区域的血-松果体屏障。
