A proximal retinal component in the primate photopic ERG a-wave.
A proximal retinal component in the primate photopic ERG a-wave.
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DOI：
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发表时间：
1994-02
影响因子：
4.4
通讯作者：
R. Bush;P. Sieving
中科院分区：
文献类型：
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作者：
R. Bush;P. Sieving
研究了在给予谷氨酸类似物期间猴的明视ERG，以确定明视a波是否仅来自光感受器。方法在40 cd/m2（3.3 log暗视troland）的稳定光适应背景下，使用200毫秒闪光或30毫秒氙光频闪闪光来诱发猴明视ERG。玻璃体内注射APB，PDA，或两者都给予阻断传输到去极化和超极化二级视网膜神经元，分别。结果注射PDA阻断水平细胞和超极化双极细胞的光反应后，部分明视a波消失。PDA敏感的组件，推测是由于活动突触后锥，是负责明视a波阈值和主导的反应超过最初的1至1.5对数单位的强度。对于较亮的刺激，该成分对明视a波的贡献是恒定的。一个非PDA敏感的贡献，a波，假定直接起源于锥，首先是明显的1至1.5个对数单位以上明视a波阈值。它在较高强度下逐渐主导a波，特别是在闪光后的早期时间点。注射PDA几乎消除了亮氙闪光灯（常用于人类临床ERG诊断测试）引起的明视a波，表明该a波可能包含显著的感受器后活动。结论灵长类动物明视ERG a波部分来源于视网膜突触后至视锥细胞的活动，特别是对于通常用于人类临床研究的明视ERG阈值附近的刺激。
PURPOSE The monkey photopic ERG was studied during administration of glutamate analogs to determine whether the photopic a-wave derives exclusively from photoreceptors. METHODS Monkey photopic ERGs were elicited using 200-msec flashes or 30-microseconds xenon photostrobe flashes on a steady light-adapting background of 40 cd/m2 (3.3 log scotopic troland). Intravitreal injections of APB, PDA, or both were given to block transmission to depolarizing and hyperpolarizing second-order retinal neurons, respectively. RESULTS After injecting PDA to block light responses of horizontal cells and hyperpolarizing bipolar cells, part of the photopic a-wave was eliminated. The PDA-sensitive component, presumed to be due to activity postsynaptic to cones, was responsible for the photopic a-wave threshold and dominated the response over the initial 1 to 1.5 log units of intensity. For brighter stimuli, this component made a constant contribution to the photopic a-wave. A non-PDA-sensitive contribution to the a-wave, presumed to originate directly from cones, was first evident 1 to 1.5 log units above photopic a-wave threshold. It progressively dominated the a-wave at higher intensities, particularly at early time points after the flash. Injecting PDA almost eliminated the photopic a-wave elicited with bright xenon photostrobe flashes that are commonly used for human clinical ERG diagnostic testing, indicating that this a-wave may contain significant postreceptoral activity. CONCLUSION The primate photopic ERG a-wave derives, in part, from retinal activity postsynaptic to cone photoreceptors, particularly for stimuli near the photopic ERG threshold that are typically used for human clinical studies.