Raviola E, Dacheux R F
Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, MA 02115.
J Neurocytol. 1990 Oct;19(5):731-6. doi: 10.1007/BF01188041.
An axonless horizontal cell (AHC) of the rabbit retina was penetrated with a microelectrode and stained with horseradish peroxidase after recording its light responses. The cell was then serially sectioned and its connections examined with the electron microscope. Physiologically, the cell exhibited cone-dominated responses and a minor rod influence known as rod aftereffect. Electron microscopy showed that this AHC was only connected to cones. Therefore, the rod aftereffect could only invade the cell through the gap junctions between the synaptic endings of rod and cone photoreceptors. In the synaptic invaginations of the cone pedicles contacting the cell, only one of the lateral elements was stained. This suggests that the two lateral elements of each cone-invaginating synapse belong to two different horizontal cells. By staining intracellularly adjacent AHCs, we showed that the two lateral processes may originate from two horizontal cells belonging to the same morphological type.
用微电极刺入兔视网膜的无轴突水平细胞（AHC），记录其光反应后用辣根过氧化物酶进行染色。然后将该细胞进行连续切片，并用电子显微镜检查其连接情况。生理上，该细胞表现出以视锥细胞为主的反应以及一种称为视杆细胞后效应的轻微视杆细胞影响。电子显微镜显示，这种AHC仅与视锥细胞相连。因此，视杆细胞后效应只能通过视杆细胞和视锥细胞光感受器突触末端之间的缝隙连接侵入该细胞。在与该细胞接触的视锥细胞足突的突触凹陷中，只有一个侧向元件被染色。这表明每个视锥细胞侵入性突触的两个侧向元件属于两个不同的水平细胞。通过对细胞内相邻的AHC进行染色，我们发现这两个侧向突起可能源自属于同一形态类型的两个水平细胞。
