Hafeez M A, Korf H W, Oksche A
Department of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan.
Cell Tissue Res. 1987 Dec;250(3):571-8. doi: 10.1007/BF00218948.
Lacertilian species display a remarkable diversity in the organization of the neural apparatus of their pineal organ (epiphysis cerebri). The occurrence of immunoreactive S-antigen and opsin was investigated in the retina and pineal organ of adult lizards, Uromastix hardwicki. In this species, numerous retinal photoreceptors displayed S-antigen-like immunoreactivity, whereas only very few pinealocytes were labeled. Immunoreactive opsin was found neither in retinal photoreceptors nor in pinealocytes. Electron microscopy showed that all pinealocytes of Uromastix hardwicki resemble modified pineal photoreceptors. A peculiar observation is the existence of a previously undescribed membrane system in the inner segments of these cells. It is evidently derived from the rough endoplasmic reticulum but consists of smooth membranes. The modified pineal photoreceptor cells of Uromastix hardwicki were never seen to establish synaptic contacts with somata or dendrites of intrapineal neurons, which are extremely rare. Vesicle-crowned ribbons are prominent in the basal processes of the receptor cells, facing the basal lamina or establishing receptor-receptor and receptor-interstitial type synaptoid contacts. Dense-core granules (60-250 nm in diameter) speak in favor of a secretory activity of the pinealocytes. Attention is drawn to the existence of receptor-receptor and receptor-interstitial cell contacts indicating intramural cellular relationships that deserve further study.
蜥蜴类物种在松果体（大脑松果体）的神经结构组织方面表现出显著的多样性。对成年蜥蜴硬尾蜥（Uromastix hardwicki）的视网膜和松果体中免疫反应性S抗原和视蛋白的存在情况进行了研究。在该物种中，许多视网膜光感受器显示出S抗原样免疫反应性，而仅有极少数松果体细胞被标记。在视网膜光感受器和松果体细胞中均未发现免疫反应性视蛋白。电子显微镜显示，硬尾蜥的所有松果体细胞都类似于经过修饰的松果体光感受器。一个特殊的观察结果是，在这些细胞的内段存在一个先前未描述的膜系统。它显然源自粗面内质网，但由光滑膜组成。硬尾蜥经过修饰的松果体光感受器细胞从未被观察到与松果体内极其罕见的神经元的胞体或树突建立突触联系。囊泡冠带在受体细胞面向基膜的基部突起中很突出，或者建立受体 - 受体和受体 - 间质型类突触联系。直径为60 - 250纳米的致密核心颗粒表明松果体细胞具有分泌活性。值得注意的是受体 - 受体和受体 - 间质细胞接触的存在，这表明壁内细胞关系值得进一步研究。
