Balkema G W
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts.
Invest Ophthalmol Vis Sci. 1988 Apr;29(4):544-9.
Albino mice and rats have elevated dark-adapted thresholds compared to normally pigmented animals. The absolute dark-adapted incremental threshold for black mice is about 1.5 log units lower than the threshold for albino mice when measured by single-unit recordings from the superior colliculus. Cell counts from the outer nuclear layer in albino mice are not significantly different from those in black mice, indicating that the elevated dark-adapted thresholds are not due to light damage of photoreceptor cells. No photoreceptor outer segment damage was found in these albino animals at the light or electron microscopic level. These experiments have been repeated in hooded and albino rats. The thresholds from albino rats were about 2 log units higher than the thresholds from pigmented rats in the dark-adapted state. The proximity of the retinal pigment epithelium (RPE) and the pigmented choroid to the photoreceptors in these animals suggests that a reduction in ocular melanin in hypopigmented animals may be causal to their elevated thresholds.
与正常色素沉着的动物相比，白化病小鼠和大鼠的暗适应阈值升高。当通过上丘的单单位记录测量时，黑小鼠的绝对暗适应增量阈值比白化病小鼠的阈值低约1.5个对数单位。白化病小鼠外核层的细胞计数与黑小鼠的细胞计数没有显著差异，这表明暗适应阈值升高不是由于光感受器细胞的光损伤。在这些白化病动物的光镜或电镜水平上未发现光感受器外段损伤。这些实验已在带帽大鼠和白化病大鼠中重复进行。在暗适应状态下，白化病大鼠的阈值比有色大鼠的阈值高约2个对数单位。这些动物中视网膜色素上皮（RPE）和色素性脉络膜与光感受器的接近程度表明，色素沉着不足的动物眼内黑色素的减少可能是其阈值升高的原因。
