Gábriel R, Wilhelm M
Department of Zoology, Janus Pannonius University, Pécs, Hungary.
Eur J Morphol. 1994 Mar;32(1):19-33.
We have performed a quantitative electron microscope study on the inner plexiform layer (IPL) of Bufo marinus retina in order to reveal the types, morphological features, densities and distributions of synapses and compare these parameters to samples derived from the visual streak area and the retinal periphery. The IPL has been subdivided into five sublayers (SLs) and the data were analysed accordingly. The density of synapses was found to be about 140.000/mm2 and was not significantly different between the central and peripheral retina. In both locations, SL3 contained the smallest number of synapses. The amacrine:bipolar presynaptic profile ratio was about 7, both in the centre and at the periphery. Amacrine-amacrine interactions greatly outnumbered other types of synapses and occurred most frequently in SL2 and 4. Bipolar cell outputs are directed mostly to amacrine-amacrine dyads, and the inputs to bipolar terminals from amacrine cells somewhat outnumber those of the outputs. The largest number of synapses directed to ganglion cells was observed in SL1 and derived from amacrine cells. The correlation between the stratification of neurochemically and morphologically characterised amacrine cells, and the morphologically and physiologically characterised ganglion cell types in the IPL are discussed.
我们对海蟾蜍视网膜的内网层（IPL）进行了定量电子显微镜研究，以揭示突触的类型、形态特征、密度和分布，并将这些参数与来自视觉条纹区域和视网膜周边的样本进行比较。IPL已被细分为五个亚层（SLs），并据此对数据进行了分析。发现突触密度约为140,000/mm²，中央视网膜和周边视网膜之间无显著差异。在这两个位置，SL3的突触数量最少。中央和周边的无长突细胞：双极细胞突触前轮廓比率约为7。无长突细胞-无长突细胞相互作用大大超过其他类型的突触，且在SL2和4中最为频繁。双极细胞的输出主要指向无长突细胞-无长突细胞二元突触，无长突细胞对双极细胞终末的输入略多于输出。在SL1中观察到指向神经节细胞的突触数量最多，且这些突触来自无长突细胞。本文讨论了神经化学和形态学特征化的无长突细胞分层与IPL中形态学和生理学特征化的神经节细胞类型之间的相关性。
