Acidification decouples gap junctions but enlarges the receptive field size of horizontal cells in carp retina
Acidification decouples gap junctions but enlarges the receptive field size of horizontal cells in carp retina
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DOI：
10.1016/j.neures.2006.10.006
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发表时间：
2007-02-01
影响因子：
2.9
通讯作者：
Yamada, Masahiro
中科院分区：
文献类型：
--
作者：
Jouhou, Hiroshi;Yamamoto, Kazunori;Yamada, Masahiro
由于相同细胞亚型之间的间隙连接耦合，视网膜水平细胞的感受野尺寸远大于其树突野尺寸。因此，水平细胞通过电耦合形成合胞体。水平细胞的基本感受野轮廓可以通过基于对从记录电极切向移动的光狭缝的响应的测量的指数函数来描述。该指数函数的空间常数与(g(s)/g(m))(1/2)成正比，其中g(s)和g(m)分别表示间隙连接电导和非间隙连接电导。通过将 pH 从 7.60 降低至 7.30 来酸化灌流溶液会降低染料偶联，使静息膜电位超极化并降低 III 型水平细胞的光响应。然而，令人惊讶的是，感受野大小显着扩大。将 pH 从 7.30 提高到 7.60 或 7.90 会产生相反的效果。这些结果与碱性细胞外pH产生比g(s)更大的增加并且增强作用于水平细胞的视锥细胞的递质释放一致。 (c) 2006 Elsevier Ireland Ltd 和日本神经科学学会。版权所有。
The receptive field size of retinal horizontal cells is much larger than their dendritic field size due to gap junctional coupling between the same sub-types of cell. Thus, horizontal cells form syncytia by electrical coupling. The basic receptive field profile of horizontal cells can be described by an exponential function based on measurement of responses to a slit of light moved tangentially from a recording electrode. The space constant of this exponential function is proportional to (g(s)/g(m))(1/2), where g(s) and g(m) represent gap junctional conductance and non-gap junctional conductance, respectively. Acidifying the superfusing solution by lowering the pH from 7.60 to 7.30 decreased the dye-coupling, hyperpolarised the resting membrane potential and reduced the photoresponses of III type horizontal cells. Surprisingly, however, the receptive field size expanded significantly. Raising the pH from 7.30 to 7.60 or 7.90 produced opposite effects. These results were consistent with alkaline extracellular pH producing a greater increase in g(m) than in g(s) and enhancing release of transmitter from cones acting upon horizontal cells. (c) 2006 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.