Stimulus-Evoked Intrinsic Optical Signals in the Retina: Pharmacologic Dissection Reveals Outer Retinal Origins
Stimulus-Evoked Intrinsic Optical Signals in the Retina: Pharmacologic Dissection Reveals Outer Retinal Origins
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DOI：
10.1167/iovs.08-3291
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发表时间：
2009-10-01
影响因子：
4.4
通讯作者：
Ts'o, Daniel
中科院分区：
文献类型：
--
作者：
Schallek, Jesse;Kardon, Randy;Ts'o, Daniel
目的.通过选择性药物阻断特定视网膜层来阐明哺乳动物视网膜刺激诱发的内源性光信号的解剖学起源。用4只成年猫研究刺激诱发的内源性信号。视网膜视觉刺激与液晶显示器（LCD）集成到一个修改后的眼底相机。用数码相机记录近红外（NIR）的诱发信号，以成像视网膜的光学反射率的变化。还记录了视网膜电图的变体（模式ERG和长脉冲ERG）作为视网膜功能的额外测量。通过玻璃体内注射电压门控钠通道阻滞剂河豚毒素（TTX）、代谢型谷氨酸受体（mGluR 6）激动剂、2-氨基-4-膦酰基丁酸（APB）和/或离子型谷氨酸受体拮抗剂顺式-2，3哌啶二羧酸（PDA）使特定视网膜层失活。在药物注射之前和之后对刺激诱发的内在信号进行成像。ERG记录和一致性瞳孔反应的测试证实了每种药物的有效性。然而，尽管药物封锁的内部视网膜（TTX）和postreceptoral视网膜电路（APB和PDA），刺激诱发的内在信号仍然基本上没有改变，从注射前的条件。同样，信号的时程在时间或形状上也没有明显的变化。研究结果表明，刺激诱发的内在信号持续注射后APB，PDA和TTX，药物，抑制内部和postreceptoral视网膜电路。这些药物给药后固有信号的持久性表明，占主导地位的固有信号可能来自外部视网膜。（Invest Ophthalmol维斯科学。2009; 50：4873-4880）DOI：10.1167/iovs.083291
PURPOSE. To elucidate the anatomic origins of stimulus-evoked intrinsic optical signals in the mammalian retina by using selective pharmacologic blockade of specific retinal layers.METHODS. Four adult cats were used to investigate the stimulus-evoked intrinsic signals. The retinas were visually stimulated with a liquid crystal display (LCD) integrated into a modified fundus camera. The evoked signals in the near infrared (NIR) were recorded with a digital camera to image the changes in the optical reflectance of the retinas. Variants of the electroretinogram (pattern ERG and long-pulse ERG) were also recorded as additional measures of retinal function. Specific retinal layers were inactivated via intravitreal injections of the voltage-gated sodium channel blocker, tetrodotoxin (TTX), the metabotropic glutamate receptor (mGluR6) agonist, 2-amino-4- phosphonobutyric acid (APB), and/or the ionotropic glutamate receptor antagonist cis-2,3 piperidinedicarboxylic acid (PDA). The stimulus-evoked intrinsic signals were imaged before and after drug injection.RESULTS. ERG recordings and tests of the consensual pupillary response confirmed the effectiveness of each drug. Yet despite the pharmacologic blockade of the inner retina (TTX) and postreceptoral retinal circuitry (APB and PDA), the stimulus-evoked intrinsic signals remained essentially unaltered from preinjection conditions. Similarly, the time course of the signal did not appreciably shift in time or shape.CONCLUSIONS. The findings demonstrate that stimulus-evoked intrinsic signals persist after injection of APB, PDA, and TTX, drugs that work to suppress inner and postreceptoral retinal circuitry. The persistence of the intrinsic signals after administration of these drugs indicates that the dominant intrinsic signals are likely to arise from the outer retina. (Invest Ophthalmol Vis Sci. 2009; 50:4873-4880) DOI: 10.1167/iovs.083291