Ohshima K, Hirai S, Nishida A, Hiramatsu K
Laboratory of Functional Anatomy, Faculty of Agriculture, Shinshu University, Nagano-ken, Japan.
Tissue Cell. 1999 Apr;31(2):126-37. doi: 10.1054/tice.1999.0031.
The fine structure and immunocytochemical localization of serotonin in the cells of the receptor line were studied in the parietal eye and pineal organ proper of the Japanese grass lizard, Takydromus tachydromoides. Typical photoreceptor cells (PC) were the predominant cell type in the receptor line of the parietal eye, the outer segments of which had regular stacks of numerous disks similar to those of cones. The pineal organ contained relatively few PCs, which showed less well-developed outer segments than those of the parietal eye. In contrast, secretory rudimentary photoreceptor cells (SRPC) accounted for the majority of receptor cells in the pineal organ. These cells were structurally characterized by whorl-like lamellar outer segments and numerous dense-cored vesicles (80-280 nm in diameter). A small number of SRPC were also found in the parietal retina, which were similar to those in the pineal organ. In the parietal-pineal complex, numerous mitochondria located in the PC were larger and rounder than those in the SRPC. In the PC, basal processes prossessed only synaptic ribbons, whereas in the SRPC some of these processes contained synaptic ribbons and others contained dense-cored vesicles, rarely having both. Serotonin-immunoreactive cells were found not only in the pineal organ but also in the parietal eye, which closely resembled the cells of the receptor line in their size and shape. Furthermore, on immunoelectron microscopy for serotonin using the protein A-gold technique, gold particles indicating serotonin-immunoreactive sites were restricted in the core of dense-cored vesicles in the SRPC of the pineal organ. Regional differences in the distributions of the PC, SRPC and serotonin-immunoreactivity were found in the parietal-pineal complex.
在日本草蜥（Takydromus tachydromoides）的顶眼和松果体中，研究了5-羟色胺在受体细胞系中的精细结构和免疫细胞化学定位。典型的光感受器细胞（PC）是顶眼受体细胞系中的主要细胞类型，其外段有规则堆叠的许多圆盘，类似于视锥细胞。松果体中PC相对较少，其外段发育程度低于顶眼的PC。相反，分泌性原始光感受器细胞（SRPC）占松果体中受体细胞的大多数。这些细胞在结构上的特征是呈螺旋状的板层外段和许多直径为80 - 280nm的致密核心小泡。在顶眼视网膜中也发现了少量SRPC，它们与松果体中的SRPC相似。在顶眼 - 松果体复合体中，PC中的许多线粒体比SRPC中的更大更圆。在PC中，基部突起仅含有突触带，而在SRPC中，一些基部突起含有突触带，另一些含有致密核心小泡，很少同时含有两者。不仅在松果体中发现了5-羟色胺免疫反应性细胞，在顶眼中也发现了，它们在大小和形状上与受体细胞系的细胞非常相似。此外，使用蛋白A - 金技术对5-羟色胺进行免疫电子显微镜观察时，表明5-羟色胺免疫反应位点的金颗粒局限于松果体SRPC中致密核心小泡的核心。在顶眼 - 松果体复合体中发现了PC、SRPC和5-羟色胺免疫反应性分布的区域差异。
