Beckers H J, Klooster J, Vrensen G F, Lamers W P
Department of Morphology, The Netherlands Ophthalmic Research Institute, Amsterdam.
Invest Ophthalmol Vis Sci. 1992 May;33(6):1979-86.
Trigeminal nerve terminals in the rat cornea and iris were ultrastructurally identified using anterograde tracing with Phaseolus vulgaris-leukoagglutinin (PHA-L). Electron microscopic immunohistochemistry was used to demonstrate the presence and localization of calcitonin gene-related peptide (CGRP) in cornea and iris. In the cornea and iris, nerve fibers were labelled with PHA-L throughout the stroma. Labelling was most obvious within varicosities, densely packed with mainly clear and a few granular vesicles and containing dark mitochondria. Numerous fibers in the stroma of cornea and iris were CGRP-positive. CGRP-positive staining was most intense within varicosities, containing mainly clear and incidentally granular vesicles and dark mitochondria, similar to the structures labelled with PHA-L. CGRP-positive varicosities packed with mainly clear and few granular vesicles also were demonstrated in fibers adjacent to the sphincter and dilator muscles of the iris. In the corneal epithelium, small terminals containing vesicles were CGRP-positive. Trigeminal nerve fibers innervating the rat cornea and iris contained numerous varicosities packed with vesicles. These areas are CGRP-positive, so it can be implied that CGRP is released from these varicosities as a response to triggering impulses. This agrees with the hypothesis that in addition to their afferent function, sensory fibers also exert an efferent modulating function.
利用菜豆白细胞凝集素（PHA-L）进行顺行示踪，在超微结构上鉴定大鼠角膜和虹膜中的三叉神经终末。采用电子显微镜免疫组织化学方法来证明降钙素基因相关肽（CGRP）在角膜和虹膜中的存在及定位。在角膜和虹膜中，整个基质内的神经纤维都被PHA-L标记。标记在膨体内最为明显，膨体内密集分布着主要为清亮的和少量颗粒状的囊泡，并含有深色线粒体。角膜和虹膜基质中的许多纤维呈CGRP阳性。CGRP阳性染色在膨体内最为强烈，膨体内主要含有清亮的囊泡，偶尔也有颗粒状囊泡和深色线粒体，类似于被PHA-L标记的结构。在虹膜括约肌和开大肌附近的纤维中也证实存在主要充满清亮囊泡和少量颗粒状囊泡的CGRP阳性膨体。在角膜上皮中，含有囊泡的小终末呈CGRP阳性。支配大鼠角膜和虹膜的三叉神经纤维含有许多充满囊泡的膨体。这些区域呈CGRP阳性，因此可以推测CGRP作为对触发冲动的反应从这些膨体中释放出来。这与以下假说相符，即感觉纤维除了具有传入功能外，还发挥传出调节功能。
