Dendritic calcium signaling in ON and OFF mouse retinal ganglion cells.
Dendritic calcium signaling in ON and OFF mouse retinal ganglion cells.
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DOI：
10.1523/jneurosci.5694-09.2010
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发表时间：
2010-05-26
期刊：
影响因子：
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通讯作者：
Detwiler PB
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文献类型：
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作者：
Margolis DJ;Gartland AJ;Euler T;Detwiler PB
视网膜神经节细胞(RGC)是视网膜的输出细胞；它们将突触输入转换为尖峰输出，将视觉信息传输到大脑。突触输入由树突接收、整合并传递到轴突的棘波起始区，树突的性质尚不清楚。在这里，我们使用同步膜片钳记录和双光子钙离子成像来研究电压和光诱发的小鼠视网膜神经节细胞树突中的钙信号，这些信号分别编码光的起始和偏移。这些结果显示了电压依赖性钙信号通路的不同。虽然On和Off细胞都表达高电压激活(HVA)的钙通道，但只有Off RGC也表达低电压激活(LVA)的钙通道。Off细胞中的LVA钙通道被静息电位的超极化失活，并在超极化电流或光的一个步骤终止时引起反弹的兴奋钙尖峰。这表明，On和Off RGC树突中电压门控钙通道的差异表达导致了这两种细胞处理视觉刺激的方式的不同。
Retinal ganglion cells (RGCs) are the output cells of the retina; they convert synaptic input into spike output that carries visual information to the brain. Synaptic inputs are received, integrated and communicated to the spike initiation zone of the axon by dendrites whose properties are poorly understood. Here simultaneous patch clamp recording and 2-photon Ca2+ imaging are used to study voltage- and light-evoked Ca2+ signals in the dendrites of identified types of mouse RGCs from parallel ON and OFF pathways, which encode the onset and offset of light, respectively. The results show pathway-specific differences in voltage-dependent Ca2+ signaling. While both ON and OFF cells express high-voltage-activated (HVA) Ca2+ channels, only OFF RGCs also express low-voltage-activated (LVA) Ca2+ channels. LVA Ca2+ channels in OFF cells are de-inactivated by hyperpolarization from the resting potential and give rise to rebound excited Ca2+ spikes at the termination of a step of either hyperpolarizing current or light. This suggests that the differential expression of voltage-gated Ca2+ channels in ON and OFF RGC dendrites contribute to differences in the way the two cell types process visual stimuli.