Downing J E, Djamgoz M B
Department of Pure and Applied Biology, Imperial College of Science, Technology and Medicine, London, England.
J Comp Neurol. 1989 Nov 22;289(4):537-53. doi: 10.1002/cne.902890402.
Horizontal cells generating photopic luminosity and biphasic/chromaticity-type S-potentials were identified and intracellularly labelled with horseradish peroxidase in the retina of the roach. The synaptic connectivity patterns of the horizontal cell dendrites within pedicles of different spectral types of cone were then quantitatively studied by electron microscopy. Luminosity-type responses were generated by H1-like horizontal cells contacting similar numbers of red- and green-sensitive cones and very few blue-sensitive cones. Most dendritic contacts were lateral to synaptic ribbons. Central contacts with ribbons were made almost exclusively within red-sensitive cone pedicles. Biphasic/chromaticity-type S-potentials were generated by H2-like horizontal cells. The dendrites of the latter contacted green- and blue-sensitive cones, both at central and lateral sites at synaptic ribbons. An attempt was made to correlate cone ribbon connectivity patterns and spectral characteristics of the horizontal cells according to several hypotheses, some proposed in earlier studies.
在蟑螂视网膜中，识别出产生明视觉光度和双相/色度型S电位的水平细胞，并用辣根过氧化物酶对其进行细胞内标记。然后通过电子显微镜定量研究不同光谱类型视锥细胞的蒂内水平细胞树突的突触连接模式。类似H1的水平细胞与数量相似的红敏和绿敏视锥细胞以及极少数蓝敏视锥细胞接触，产生光度型反应。大多数树突接触位于突触带的侧面。与突触带的中央接触几乎仅在红敏视锥细胞的蒂内形成。类似H2的水平细胞产生双相/色度型S电位。后者的树突在突触带的中央和侧面位点与绿敏和蓝敏视锥细胞接触。根据一些假设，试图将视锥细胞带连接模式与水平细胞的光谱特征相关联，其中一些假设是早期研究中提出的。
