POLYAXONAL AMACRINE CELLS OF RABBIT RETINA - MORPHOLOGY AND STRATIFICATION OF PA1 CELLS
POLYAXONAL AMACRINE CELLS OF RABBIT RETINA - MORPHOLOGY AND STRATIFICATION OF PA1 CELLS
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DOI：
10.1002/cne.903160402
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发表时间：
1992-02-22
影响因子：
2.5
通讯作者：
FAMIGLIETTI, EV
中科院分区：
文献类型：
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作者：
FAMIGLIETTI, EV
多轴突无长突细胞是一类新的无长突细胞，具有一到六个分支的轴突样突起，与中枢神经系统其他地方发现的高尔基 II 型细胞的轴突非常相似。在我们在兔视网膜中识别的四种类型的多轴突无长突细胞中，其中三种已在之前的简短通讯中描述过，其中一种是本文的主题。1型多轴突（PA1）无长突细胞的细胞体比高尔基体制备物中的大多数无长突细胞更大，平均直径约为13μm。它们通常位于内丛状层 (IPL) 中间的间质中，尽管也有一些存在于无长突细胞和神经节细胞层中。轴突和树突在 IPL 中部、a/b 层下边界附近广泛分层。稀疏分枝的树突具有传统的外观，以狭窄的角度分枝，并产生较小的子分枝，这些子分枝朝着其末端逐渐变细。树突的一个不寻常的特征是一些末端分支的锯齿形路线。小的、带蒂的棘簇在近端树突上很常见，而轴突上几乎不存在棘。轴突从体细胞 50 微米以内的近端树突中出现，并且更罕见地从体细胞中出现，在逐渐变细的初始段中，通常被一两个大肿胀中断。随后的分枝是大角度的，并且在从母枝到子枝的过渡中保持细口径。轴突分支的均匀厚度不时被路过的纽扣打断。虽然树突树的范围很大，距细胞体的径向范围超过 500 μm，但对于距视觉条纹几毫米的细胞，轴突树要大得多，其径向范围以毫米为单位。 PA1无长突细胞被认为在其功能组织中是极化的，具有主要的受体树突树和主要的传递性轴突树。PA1无长突细胞与nab锥双极细胞以及在a/b下层边界处与某些小簇状无长突细胞和神经节细胞共层。 IPL a/b 层下边界处的轴突和树突的共分层表明 PA1 无长突细胞是 IPL 中部神经活动的重要调节剂，影响 ON 和 OFF 反应，并且可能选择性地影响 ON-OFF 细胞。
Polyaxonal amacrine cells are a new class of amacrine cell bearing one to six branching, axon-like processes, closely resembling the axons of Golgi type II cells found elsewhere in the central nervous system. Of the four types of polyaxonal amacrine cell that we have recognized in rabbit retina, three have been described previously in brief communications, and one is the subject of this paper.Type 1 polyaxonal (PA1) amacrine cells have larger cell bodies than most amacrine cells in Golgi preparations, averaging about 13-mu-m in diameter. These are typically positioned interstitially in the middle of the inner plexiform layer (IPL), although some are also found in the amacrine and ganglion cell layers. Axons and dendrites are broadly stratified in the middle of the IPL, in the vicinity of the a/b sublaminar border. Sparsely branching dendrites have a conventional appearance, branching at a narrow angle, and giving rise to smaller daughter branches, which taper gradually toward their termination. An unusual feature of the dendrites is the zig-zag course of some terminal branches. Clusters of small, pedunculated spines are common on proximal dendrites, and spines are virtually absent on axons.Axons emerge from proximal dendrites within 50-mu-m of the soma, and more rarely from the soma, in a tapering initial segment, commonly interrupted by one or two large swellings. Subsequent branching is at a wide angle, and the fine caliber is maintained in the transition from parent to daughter branches. The uniform thickness of the axonal branches is interrupted at intervals by boutons en passant. Although the extent of the dendritic tree is large, exceeding 500-mu-m in radial extent from the cell body, for cells a few millimeters distant from the visual streak, the axonal tree is much larger, and its radial extent is measured in millimeters. PA1 amacrine cells are believed to be polarized in their functional organization, with a primarily recipient dendritic tree and a primarily transmissive axonal tree.PA1 amacrine cells co-stratify with nab cone bipolar cells and with certain small tufted amacrine and ganglion cells at the a/b sublaminar border. The co-stratification of both axons and dendrites at the a/b sublaminar border of the IPL suggests that PA1 amacrine cells are important modulators of neural activity in the middle of the IPL, affecting both ON and OFF responses, and perhaps ON-OFF cells selectively.