Bilotta Joseph, Trace Sara E, Vukmanic Eric V, Risner Michael L
Department of Psychology and Biotechnology Center, Western Kentucky University, 1 Big Red Way, Bowling Green, KY 42101, USA.
Int J Dev Neurosci. 2005 Feb;23(1):15-25. doi: 10.1016/j.ijdevneu.2004.09.004.
The electroretinogram (ERG) is a commonly used measure to examine retinal processing in both basic and clinical research. The purpose of this study was to determine the retinal mechanisms responsible for the developmental differences found in the zebrafish ERG waveform. The ERG of young zebrafish possesses a voltage-negative response to ultraviolet- and short-wavelength stimuli, but not to middle- and long-wavelength stimuli; the ERG of adult zebrafish does not possess this response component. ERGs were obtained from young zebrafish before and after the introduction of either aspartate, or a combination of APB (DL-2-amino-4-phosphonobutyric acid) and PDA (cis-2,3-piperidinedicarboxylic acid) in order to suppress the responses of various types of retinal neurons. Log irradiance versus response amplitude functions of the ERG response to 200-ms stimuli of various wavelengths at various times following stimulus onset (70 and 120 ms) was derived as well as spectral sensitivity. Aspartate eliminated all voltage-positive responses regardless of stimulus wavelength; irradiance-response functions following aspartate were similar to the early responses of young control fish to ultraviolet- and short-wavelength stimuli. APB + PDA produced similar but not identical results as aspartate, suggesting that the combination of these agents does not completely eliminate all post-receptoral contributions to the ERG. Spectral sensitivity functions derived from aspartate-exposed subjects at various time measurements were dominated by contributions from ultraviolet- and short-wavelength-sensitive cone types. These wavelength-dependent ERG responses are similar to those found in humans with enhanced S-cone syndrome. Finally, ERG waveform differences across stimulus wavelength suggest that the circuitry of ultraviolet- and short-wavelength cone types is different to that of middle- and long-wavelength cone types in young zebrafish.
视网膜电图（ERG）是基础研究和临床研究中用于检测视网膜功能的常用手段。本研究旨在确定导致斑马鱼ERG波形发育差异的视网膜机制。幼年斑马鱼的ERG对紫外线和短波长刺激呈现电压负向反应，但对中波长和长波长刺激无此反应；成年斑马鱼的ERG则不具备这种反应成分。在幼年斑马鱼引入天冬氨酸或APB（DL-2-氨基-4-磷酸丁酸）与PDA（顺式-2,3-哌啶二羧酸）组合前后记录ERG，以抑制各类视网膜神经元的反应。得出了刺激开始后不同时间（70和120毫秒）对各种波长200毫秒刺激的ERG反应的对数辐照度与反应幅度函数以及光谱敏感性。天冬氨酸消除了所有电压正向反应，无论刺激波长如何；天冬氨酸处理后的辐照度-反应函数类似于幼年对照鱼对紫外线和短波长刺激的早期反应。APB + PDA产生了与天冬氨酸相似但不完全相同的结果，表明这些药剂的组合并未完全消除ERG中所有感受器后成分的贡献。在不同时间测量中从天冬氨酸处理的受试者得出的光谱敏感性函数主要由对紫外线和短波长敏感的视锥细胞类型的贡献主导。这些波长依赖性ERG反应类似于在患有增强型S视锥综合征的人类中发现的反应。最后，不同刺激波长下的ERG波形差异表明，幼年斑马鱼中紫外线和短波长视锥细胞类型的电路与中波长和长波长视锥细胞类型的电路不同。
