Zhu B S, Gibbins I L
Department of Anatomy and Histology, School of Medicine, Flinders University of South Australia, Adelaide, Australia.
Vis Neurosci. 1997 Nov-Dec;14(6):1089-96. doi: 10.1017/s0952523800011792.
The entire population of ganglion cells in the retina of the toad Bufo marinus was labeled by retrograde transport of a lysine-fixable biotinylated dextran amine of 3000 molecular weight. Synaptic connections between bipolar, amacrine, and ganglion cells in the inner plexiform layer were quantitatively analyzed, with emphasis on synaptic inputs to labeled ganglion cell dendrites. Synapses onto ganglion cell dendrites comprised 47% of a total of 1234 identified synapses in the inner plexiform layer. Approximately half of the bipolar or amacrine cell synapses were directed onto ganglion cell dendrites, while the rest were made mainly onto amacrine cell dendrites. Most of the synaptic inputs to ganglion cell dendrites derived from amacrine cell dendrites (84%), with the rest from bipolar cell terminals. Synaptic inputs to ganglion cell dendrites were distributed relatively uniformly throughout all sublaminae of the inner plexiform layer. The present study provides unambiguous identification of ganglion cell dendrites including very fine processes, enabling a detailed analysis of the types and distribution of synaptic inputs from the bipolar and amacrine cell to the ganglion cells. The retrograde tracing technique used in the present study will prove to be a useful tool for identifying synaptic inputs to ganglion cell dendrites from neurochemically identified bipolar and amacrine cell types in the retina.
通过逆行运输分子量为3000的赖氨酸固定生物素化葡聚糖胺，标记了海蟾蜍视网膜中所有的神经节细胞。对内网状层中双极细胞、无长突细胞和神经节细胞之间的突触连接进行了定量分析，重点是标记的神经节细胞树突的突触输入。在内网状层总共1234个已识别的突触中，神经节细胞树突上的突触占47%。大约一半的双极细胞或无长突细胞突触指向神经节细胞树突，其余的主要形成于无长突细胞树突上。神经节细胞树突的大多数突触输入来自无长突细胞树突（84%），其余来自双极细胞终末。神经节细胞树突的突触输入在内网状层的所有亚层中分布相对均匀。本研究明确鉴定了神经节细胞树突，包括非常细小的突起，从而能够详细分析双极细胞和无长突细胞到神经节细胞的突触输入类型和分布。本研究中使用的逆行追踪技术将被证明是一种有用的工具，用于从视网膜中神经化学鉴定的双极细胞和无长突细胞类型识别神经节细胞树突的突触输入。
