Calderone Jack B, Jacobs Gerald H
Neuroscience Research Institute and Department of Psychology, University of California, Santa Barbara 93106, USA.
Vis Neurosci. 2003 Jan-Feb;20(1):11-7. doi: 10.1017/s0952523803201024.
The spectral mechanisms of the ferret (Mustela putorious furo) were studied with electroretinogram (ERG) flicker photometry. Variations in adaptation state and flicker rate were used to define corneally based spectral sensitivities for the three classes of receptor present in the retina of this mustelid-rods (lambdamax = 505 nm), S cones (430 nm), and L cones (558 nm). The retinal distributions of the two classes of cone were determined using opsin antibody labeling. Ferret retinas contain a total of about 1.3 million cones with L cones outnumbering S cones in a ratio of approximately 14:1. ERGs were also recorded using 18.75-Hz flickering stimuli that were designed to isolate signals from individual cone classes. The contrast/response functions for signals originating from both S and L cones were linear over low-to-moderate levels of contrast, but with greatly different slopes for the two cone types. The L:S contrast gain ratio derived from a comparison of these slopes, as well as inferences drawn from another experiment in which responses to various combinations of L- and S-cone activation were analyzed, suggest that contributions of these two cone types to the flicker ERG have a relative weighting of about 4:1 to 5:1 (L/S).
利用视网膜电图（ERG）闪烁光度法研究了雪貂（白鼬）的光谱机制。通过改变适应状态和闪烁频率，确定了这种鼬科动物视网膜中存在的三类感受器基于角膜的光谱敏感度，即视杆细胞（λmax = 505 nm）、S视锥细胞（430 nm）和L视锥细胞（558 nm）。使用视蛋白抗体标记法确定了两类视锥细胞在视网膜中的分布。雪貂视网膜总共约有130万个视锥细胞，L视锥细胞的数量比S视锥细胞多，比例约为14:1。还使用18.75 Hz的闪烁刺激记录ERG，该刺激旨在分离来自各个视锥细胞类别的信号。来自S视锥细胞和L视锥细胞的信号的对比度/响应函数在低到中等对比度水平上呈线性，但两种视锥细胞类型的斜率有很大差异。通过比较这些斜率得出的L:S对比度增益比，以及从另一个分析对L视锥细胞和S视锥细胞激活的各种组合的响应的实验中得出的推论表明，这两种视锥细胞类型对闪烁ERG的贡献的相对权重约为4:1至5:1（L/S）。
