Hayes J M, Balkema G W
Biology Department, Boston College, Chestnut Hill, Massachusetts 02167.
Behav Genet. 1993 Jul;23(4):395-403. doi: 10.1007/BF01067442.
In previous electrophysiological experiments from hypopigmented animals (mice, rats, rabbits), single-unit recordings from both retinal ganglion axons and cells in the superior colliculus have demonstrated an increase in threshold in the dark-adapted state which is roughly proportional to the ocular melanin concentration. In the present study we compared an albino mouse strain which is relatively resistant to light damage and the beige mouse mutant to their wild-type controls in a situation that involved unanesthetized, unrestrained mice as a control to the electrophysiological single unit experiments. We used a six-chambered water maze. Animals were trained to swim to an illuminated ramp until their performances leveled off (about 10 days). The animals were then dark-adapted for 24 h and tested after reducing the luminance level of the water maze. We found that the albino mice failed to find the ramp when the luminance fell to 1.58 x 10(-3) cd/m2 (p < or = .0001), the beige mice failed at 2.00 x 10(-4) cd/m2 (p < or = .0001), and the normally pigmented controls performed to 5.00 x 10(-5) cd/m2 (p < or = .0001). These results support our previous findings that the sensitivity defect in hypopigmented animals is proportional to the degree of ocular hypopigmentation.
在之前对色素减退动物（小鼠、大鼠、兔子）进行的电生理实验中，从视网膜神经节轴突和上丘细胞进行的单单位记录表明，在暗适应状态下阈值升高，且大致与眼部黑色素浓度成正比。在本研究中，我们将一种对光损伤相对有抗性的白化小鼠品系和米色小鼠突变体与其野生型对照进行比较，实验情况涉及未麻醉、未受束缚的小鼠，以此作为电生理单单位实验的对照。我们使用了一个六室水迷宫。训练动物游向一个有光照的斜坡，直到它们的表现趋于平稳（约10天）。然后让动物进行24小时暗适应，在降低水迷宫的亮度水平后进行测试。我们发现，当亮度降至1.58×10⁻³坎德拉/平方米时，白化小鼠找不到斜坡（p≤0.0001），当亮度降至2.00×10⁻⁴坎德拉/平方米时，米色小鼠找不到斜坡（p≤0.0001），而正常色素沉着的对照组在亮度降至5.00×10⁻⁵坎德拉/平方米时仍能找到斜坡（p≤0.0001）。这些结果支持了我们之前的发现，即色素减退动物的敏感性缺陷与眼部色素减退程度成正比。
