Henderson Dori, Miller Robert F
Department of Neuroscience, University of Minnesota, Minneapolis 55414, USA.
Vis Neurosci. 2003 Mar-Apr;20(2):141-52. doi: 10.1017/s0952523803202054.
We have evaluated the spatial distribution of low-voltage-activated calcium currents in ganglion cells of the tiger salamander retina. Whole-cell recordings were obtained from ganglion cells in a retinal slice preparation and from acutely dissociated ganglion cells that were identified through retrograde dye injection. In single dissociated cells, we estimated the magnitude (pA) and current density (pA/pF) of LVA currents in ganglion cells, both with and without dendritic processes. Ganglion cells that retained a portion of their dendritic arbor had larger LVA calcium currents and higher LVA current densities than those which lacked processes. When cell capacitance measurements were used to derive the surface area of the soma and dendritic processes, we concluded that a higher LVA current density was present in the dendrites; we estimate that, on average, the current density in the dendrites is approximately five times that of the soma. The presence of a significant density of LVA calcium channels in the dendrites of ganglion cells suggests that they could be involved in a number of cellular functions, including dendritic integration of synaptic currents, impulse generation, and homeostatic functions related to changes in the intradendritic calcium concentration.
我们评估了虎螈视网膜神经节细胞中低电压激活钙电流的空间分布。全细胞膜片钳记录是从视网膜切片制备中的神经节细胞以及通过逆行染料注射鉴定的急性解离神经节细胞中获得的。在单个解离细胞中，我们估计了有和没有树突过程的神经节细胞中低电压激活电流的大小（pA）和电流密度（pA/pF）。保留部分树突 Arbor 的神经节细胞比那些没有树突的细胞具有更大的低电压激活钙电流和更高的低电压激活电流密度。当使用细胞电容测量来推导胞体和树突过程的表面积时，我们得出结论，树突中存在更高的低电压激活电流密度；我们估计，平均而言，树突中的电流密度约为胞体的五倍。神经节细胞树突中存在大量低电压激活钙通道表明它们可能参与多种细胞功能，包括突触电流的树突整合、冲动产生以及与树突内钙浓度变化相关的稳态功能。
