Retinal bipolar cell input mechanisms in giant danio. III. ON-OFF bipolar cells and their color-opponent mechanisms.
Retinal bipolar cell input mechanisms in giant danio. III. ON-OFF bipolar cells and their color-opponent mechanisms.
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巨型丹尼奥的视网膜双极细胞输入机制。
DOI：
10.1152/jn.00271.2004
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发表时间：
2005
影响因子：
2.5
通讯作者：
Dowling,JohnE
中科院分区：
文献类型：
--
作者：
Wong,KwoonY;Dowling,JohnE
采用全细胞膜片钳记录技术，对巨大斑马鱼视网膜切片中的视锥细胞驱动的离体双极细胞（Cabs）进行谷氨酸受体和光诱发反应研究。在钴、印防己毒素和士的宁的存在下膨化特定的激动剂，以鉴定这些细胞上的谷氨酸受体。大多数Cabs对α-氨基-3-羟基-5-甲基-4-异恶唑丙酸酯（AMPA）/红藻氨酸受体激动剂红藻氨酸和兴奋性氨基酸转运蛋白（EAAT）底物天冬氨酸均有反应，且两种反应均定位于树突。红藻氨酸产生去极化，而天冬氨酸产生超极化，表明AMPA/红藻氨酸受体是符号保留的，而EAAT是符号反转的。在白色光刺激下，有的Cabs产生双极细胞样反应，有的Cabs产生非双极细胞样反应，但也有许多细胞的反应兼有非双极细胞成分和双极细胞成分。在适当的颜色中心选择性刺激，许多出租车响应短波长和长波长相反的极性，因此双颜色对手。对白色或彩色刺激的反应的去极化成分被EAAT阻断剂1-苏型-β-苄氧基天冬氨酸（TBOA）抑制，而超极化成分被AMPA/红藻氨酸受体拮抗剂6，7-二硝基喹喔啉-2，3-二酮（DNQX）抑制。这些结果与EAATs和AMPA/红藻氨酸受体参与Cabs光诱发反应的产生以及它们分别赋予Cabs细胞onandoffbipolar细胞特性的假设一致。驾驶室可以通过EAAT从某些视锥细胞接收输入，通过AMPA/红藻氨酸受体从其他视锥细胞接收输入，从而产生双色-对手中心反应。
Whole cell patch recording was performed from morphologically identified cone-drivenon-offbipolar cells (Cabs) in giant danio retinal slices to study their glutamate receptors and light-evoked responses. Specific agonists were puffed in the presence of cobalt, picrotoxin, and strychnine to identify glutamate receptors on these cells. Most Cabs responded to both the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptor agonist kainate and the excitatory amino acid transporter (EAAT) substrated-aspartate, and both responses were localized to the dendrites. Kainate generated depolarizations whereasd-aspartate hadErevclose toECland generated hyperpolarizations, indicating that the AMPA/kainate receptors are sign-preserving, whereas the EAATs are sign-inverting. In response to white light, some Cabs gaveonbipolar cell-like responses whereas others gaveoffbipolar cell-like ones, but many cells' responses had bothonandoffbipolar cell components. In response to appropriately colored center-selective stimuli, many Cabs responded to short and long wavelengths with opposite polarities and were thus double color-opponent. The depolarizing components of the responses to white or colored stimuli were suppressed by the EAAT blockerdl-threo-β-benzyloxyaspartate (TBOA), whereas the hyperpolarizing components were reduced by the AMPA/kainate receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX). These results are consistent with the hypothesis that both EAATs and AMPA/kainate receptors are involved in the generation of light-evoked responses in Cabs and that they confer these cells withonandoffbipolar cell properties, respectively. Cabs can generate double color-opponent center responses by receiving inputs from certain cones through EAATs and from other cones through AMPA/kainate receptors.