Wong R O
National Vision Research Institute of Australia, Carlton, Vic.
J Comp Neurol. 1990 Apr 1;294(1):109-32. doi: 10.1002/cne.902940109.
The postnatal dendritic maturation of small field type 1 (SF1), medium field type 1 (MF1) and type 2 (MF2), and large field type 1 (alpha) ganglion cells in the rabbit retina was compared qualitatively and quantitatively. Dendritic tree structure was revealed by intracellular injection of the fluorescent dye Lucifer yellow, and the stained cells were then morphologically separated on the basis of some area, dendritic field size, total dendritic length, number of nodes, and mean internodal distance. Cells in the visual streak and an area inferior to the streak were sampled from retinae between birth and adulthood. The dendrites of all studied classes of rabbit ganglion cells were extensively covered by short spine-like appendages. As in cat retina, many dendritic spines disappeared by the end of the third postnatal week, at which stage the adult dendritic form could be recognised. However, there was differential loss in the number of spines from the dendrites of the four cell classes. In both the streak and inferior retina, adult SF1 cells had the same number of spines/dendritic unit length throughout postnatal life, whereas MF1 and MF2 ganglion cells lost at least half of their number of spines/unit dendritic length by maturity. Alpha ganglion cells lost virtually all their dendritic spines by adulthood. In both retinal locations, there were small changes in the number of nodes (dendritic branch points) of small field and medium field ganglion cells but alpha cells lost between 70 to 80% of their nodes by adulthood. The dendrites of ganglion cells with contrasting morphology thus undergo differential remodelling during postnatal maturation. The completion of the period of dendritic remodelling coincided with the first appearance of adult receptive field organisation, suggesting that structural remodelling, in particular that involving dendritic spines, may be associated with the development of the cell's synaptic circuitry. The dendrites of neighbouring postnatal ganglion cells in the rabbit retina also grow by different amounts; the increase in dendritic tree area, total dendritic length, and mean internodal distances of alpha cells exceeded that of small field and medium field cells in corresponding retinal positions. This implies that retinal dendrites elongate by active growth rather than by "passive stretching."
对兔视网膜中小场1型（SF1）、中场1型（MF1）和2型（MF2）以及大场1型（α）神经节细胞的产后树突成熟进行了定性和定量比较。通过向细胞内注射荧光染料路西法黄来揭示树突结构，然后根据面积、树突野大小、总树突长度、节点数量和平均节间距离对染色细胞进行形态学分类。从出生到成年期的视网膜中，采集视条纹和条纹下方区域的细胞。所有研究的兔神经节细胞类别的树突都被短的棘状附属物广泛覆盖。与猫视网膜一样，许多树突棘在出生后第三周结束时消失，此时可以识别出成年树突形态。然而，这四类细胞树突上的棘数量存在差异减少。在视条纹和视网膜下方区域，成年SF1细胞在整个产后生命中每单位树突长度的棘数量相同，而MF1和MF2神经节细胞在成熟时至少失去了一半的每单位树突长度的棘数量。α神经节细胞在成年时几乎失去了所有的树突棘。在两个视网膜位置，小场和中场神经节细胞的节点（树突分支点）数量变化较小，但α细胞在成年时失去了70%至80%的节点。因此，形态不同的神经节细胞的树突在产后成熟过程中经历了不同的重塑。树突重塑期的完成与成年感受野组织的首次出现同时发生，这表明结构重塑，特别是涉及树突棘的重塑，可能与细胞突触回路的发育有关。兔视网膜中相邻的产后神经节细胞的树突生长量也不同；α细胞的树突野面积、总树突长度和平均节间距离的增加超过了相应视网膜位置的小场和中场细胞。这意味着视网膜树突是通过主动生长而不是“被动拉伸”来延长的。
