Two types of cone bipolar cells express voltage-gated Na+ channels in the rat retina
Two types of cone bipolar cells express voltage-gated Na+ channels in the rat retina
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DOI：
10.1017/s0952523808080851
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发表时间：
2008-09-01
影响因子：
1.9
通讯作者：
Pan, Zhu-Hua
中科院分区：
文献类型：
--
作者：
Cui, Jinjuan;Pan, Zhu-Hua
在大鼠视网膜的两组锥体双极细胞（CBCs）中发现电压门控性Na+通道。第一组轴突终末位于内丛状层（IPL）的第2层下，并与OFF-胆碱能带部分重叠。这组被鉴定为3型CBC。第二组的轴突终末在IPL的sublamina 3中分层，稍微远离ON-胆碱能带。第二组细胞类似于5型CBC。此外，我们还观察到另一组ON型CBCs，其终末分层与第二组相似。然而，后一组没有显示出任何Na+电流，而是表现出大的超极化激活的环核苷酸门控阳离子电流，表明存在生理上不同的5型CBC的两个亚类。两组Na+表达双极细胞都能够产生快速河豚毒素敏感的动作电位，如电流注射所示。在其中一些细胞中还观察到多个尖峰样电位。本研究结果为深入了解视网膜双极细胞电压型Na+通道在视网膜信息加工中的作用提供了有价值的信息。
Two groups of retinal cone bipolar cells (CBCs) in rats were found to express voltage-gated Na+ channels. The axon terminals of the first group stratify in sublamina 2 of the inner plexiform layer (IPL) and partially overlap with the OFF-cholinergic band. This group was identified as type 3 CBCs. The axon terminals of the second group stratify in sublamina 3 of the IPL, slightly distal to the ON-cholinergic band. Cells of this second group resemble type 5 CBCs. In addition, we observed another group of ON-type CBCs with terminal stratification similar to that of the second group. However, this latter group did not show any Na+ current, instead exhibiting a large hyperpolarization-activated cyclic nucleotide-gated cation current, suggesting the existence of two subclasses of physiologically distinct type 5 CBCs. Both groups of Na+-expressing bipolar cells were capable of generating a rapid tetrodotoxin-sensitive action potential as revealed by current injection. Multiple spike-like potentials were also observed in some of these cells. Results of this study provide valuable insights into the function of voltage Na+ channels of retinal bipolar cells in retinal processing.