Wu Mu-Ling, Chiao Chuan-Chin
Institute of Molecular Medicine, National Tsing Hua University, Hsinchu, 30013, Taiwan.
Brain Res. 2007 Sep 19;1170:13-9. doi: 10.1016/j.brainres.2007.06.091. Epub 2007 Jul 27.
Bipolar cells are responsible for transmitting light signals from the photoreceptors to the ganglion cells in the vertebrate retina. Their maturation process is not only important for establishing normal visual function, but may also underlie the dendritic remodeling of ganglion cells during development. It is known that light deprivation affects the synaptic connections of ganglion cells in the mammalian retina, but little is known about impact of visual experience on bipolar cell development. We used dye injection and gene gun labeling to identify bipolar cells, and characterized their morphological differentiation in normal-reared and dark-reared rabbits. Our results show that immature bipolar cells can be found as early as P1-3, and most characteristic bipolar cells can be identified during P4-6. More importantly, we found that light deprivation causes a delay rather than a permanent arrest of bipolar cell maturation in the rabbit retina. By eye opening at P10-11, both normal-reared and dark-reared rabbits possessed adult-like bipolar cells. This suggests that visual experience has a facilitating effect on the morphological differentiation of bipolar cells.
双极细胞负责将脊椎动物视网膜中光感受器的光信号传递给神经节细胞。它们的成熟过程不仅对于建立正常视觉功能很重要，而且可能也是神经节细胞在发育过程中树突重塑的基础。已知光剥夺会影响哺乳动物视网膜中神经节细胞的突触连接，但关于视觉经验对双极细胞发育的影响却知之甚少。我们使用染料注射和基因枪标记来识别双极细胞，并对正常饲养和暗饲养兔子中双极细胞的形态分化进行了表征。我们的结果表明，早在出生后1 - 3天就能发现未成熟的双极细胞，而在出生后4 - 6天能识别出大多数具有特征性的双极细胞。更重要的是，我们发现光剥夺会导致兔子视网膜中双极细胞成熟延迟，而非永久性停滞。在出生后10 - 11天睁眼时，正常饲养和暗饲养的兔子都拥有类似成年动物的双极细胞。这表明视觉经验对双极细胞的形态分化具有促进作用。
