Mariani A P
J Comp Neurol. 1985 Mar 22;233(4):553-63. doi: 10.1002/cne.902330412.
The retinas of most vertebrates contain two or more morphologically distinct types of horizontal cell, and usually one of these types lacks an axon. Among mammals, in which two types are observed, primates are exceptional in that both types of horizontal cell have axons. It then seemed of interest to study the horizontal cells of tree shrews (Tupaia glis), insectivores thought to be closely related to primates. Golgi impregnations of whole, flat-preparations revealed two types of horizontal cell. Uniaxonal cells have a compact dendritic organization with clusters of terminals, and a single thin axon with short collaterals and a few terminals, located along its length. Multiaxonal cells have a relatively large dendritic tree, and arising from the tips of about four to eight dendrites of an individual cell are thin axonlike processes which terminate as profusely branched telodendritic arborizations. This identification of the multiaxonal horizontal cells in Tupaia retina is the first time any vertebrate horizontal cell has been found to possess more than a single axon. A comparison of horizontal cells in tree shrew, monkey, cat, and squirrel retinas shows a remarkable morphological diversity within this class of mammalian retinal neuron.
大多数脊椎动物的视网膜含有两种或更多种形态上不同的水平细胞类型，通常其中一种类型没有轴突。在观察到两种类型水平细胞的哺乳动物中，灵长类动物是例外，因为这两种类型的水平细胞都有轴突。因此，研究树鼩（Tupaia glis）的水平细胞似乎很有意思，树鼩是一种食虫动物，被认为与灵长类动物关系密切。对完整扁平标本的高尔基染色显示出两种类型的水平细胞。单轴突细胞具有紧密的树突组织，带有终末簇，以及一条细的单轴突，有短侧支和一些沿其长度分布的终末。多轴突细胞具有相对较大的树突树，从单个细胞的大约四到八个树突尖端发出的是细的轴突样突起，它们终止于大量分支的终末树状分支。在树鼩视网膜中对多轴突水平细胞的这种识别首次发现任何脊椎动物的水平细胞拥有不止一条轴突。对树鼩、猴子、猫和松鼠视网膜中的水平细胞进行比较显示，在这类哺乳动物视网膜神经元中存在显著的形态多样性。
