Horizontal cells feed back to cones by shifting the cone calcium-current activation range
Horizontal cells feed back to cones by shifting the cone calcium-current activation range
复制标题
DOI：
10.1016/s0042-6989(96)00142-3
复制
发表时间：
1996-12-01
期刊：
影响因子：
1.8
通讯作者：
Spekreijse, H
中科院分区：
文献类型：
--
作者：
Verweij, J;Kamermans, M;Spekreijse, H
我们研究了孤立金鱼视网膜中水平细胞到视锥细胞的反馈，发现周围的刺激会引起内向电流和缓慢发展的外向电流。周围诱发的电流被谷氨酸拮抗剂 6,7-二硝基喹喔啉-2,3-二酮 (DNQX) 阻断，并且与水平细胞反应一样，最有效地由大刺激诱发。这表明电流是由水平单元的反馈引起的。周围诱发的内向电流既不会被印防己毒素阻断，也不会被氯化物携带。相反，它由钙携带，并引发缓慢发展的钙依赖性氯电流。我们无法通过调节细胞外 GABA 浓度来模拟周围诱发电流。我们得出的结论是，当水平细胞超极化时，它们通过将锥体钙电流激活范围转移到更负的电位来反馈给锥体。这种类型的反馈直接针对钙电流，几乎不影响接收神经元的膜电位，但有效地调节其突触输出。版权所有 (C) 1996 爱思唯尔科学有限公司
We studied feedback from horizontal cells to cones in isolated goldfish retinae and found that surround stimuli evoke an inward current and a slowly developing outward current. The surround-evoked currents are blocked by the glutamate antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX) and are, like horizontal cell responses, most effectively evoked by large stimuli. This indicates that the currents are caused by feedback from horizontal cells. The surround-evoked inward current is neither blocked by picrotoxin nor carried by chloride. Instead, it is carried by calcium, and it triggers a slowly developing calcium-dependent chloride current. We were unable to mimick the surround-evoked currents by modulating the extracellular GABA concentration. We conclude that when horizontal cells hyperpolarize they feed back to the cones by shifting the cone calcium-current activation range to more negative potentials. This type of feedback, directly targeted at the calcium current, scarcely influences the membrane potential of the receiving neuron, but effectively modulates its synaptic output. Copyright (C) 1996 Elsevier Science Ltd