Kemp C M, Jacobson S G
Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, FL 33101.
Exp Eye Res. 1992 Jun;54(6):947-56. doi: 10.1016/0014-4835(92)90159-p.
Visual pigment in normal miniature poodles and those with progressive rod-cone degeneration (prcd), a late-onset autosomal recessive photoreceptor degeneration, has been studied using imaging fundus reflectometry (IFR). The stage to which the disease had advanced in the animals with prcd was assessed with electroretinography (ERG). Measurements were carried out on seven affected, two heterozygous and three homozygous normal animals. The IFR measurements showed that the in situ difference spectrum of visual pigment measured in the central retina of the normal poodle is typical of vertebrate rhodopsin, with a maximum at about 510 nm. Rhodopsin regeneration following extensive bleaches continues for up to 70 min. In poodles with prcd, rhodopsin is spectrally normal and regenerates at normal rates. In young affected animals under 1 year of age, the final levels of rhodopsin could already be substantially reduced. Serial measurements of visual pigment in these dogs showed differences in the degree and spatial pattern of pigment loss and rate of progression between animals. The extent of visual pigment loss also differed among the older (greater than 4.5 years) affected animals: while in one animal no pigment could be detected, in another a central band of retina was relatively spared, and significant levels of visual pigment were measured within it. Pigment levels measured within the central 25 degrees of the retinas of poodles heterozygous for prcd were lower than those in normal animals, even though their ERGs were within the normal range.
已使用眼底反射成像术（IFR）对正常迷你贵宾犬以及患有进行性视杆视锥细胞营养不良（prcd，一种迟发性常染色体隐性遗传性光感受器变性疾病）的贵宾犬的视觉色素进行了研究。通过视网膜电图（ERG）评估患有prcd的动物的疾病进展阶段。对7只患病、2只杂合子和3只纯合子正常动物进行了测量。IFR测量结果表明，在正常贵宾犬中央视网膜测量的视觉色素原位差异光谱是典型的脊椎动物视紫红质光谱，其最大值约在510nm处。大量漂白后视紫红质的再生持续长达70分钟。在患有prcd的贵宾犬中，视紫红质在光谱上正常且以正常速率再生。在1岁以下的年轻患病动物中，视紫红质的最终水平可能已经大幅降低。对这些犬的视觉色素进行的连续测量显示，不同动物之间色素损失的程度和空间模式以及进展速率存在差异。在年龄较大（大于4.5岁）的患病动物中，视觉色素损失的程度也有所不同：在一只动物中未检测到色素，而在另一只动物中，视网膜中央带相对未受影响，且在其中测量到了显著水平的视觉色素。即使prcd杂合子贵宾犬视网膜中央25度范围内的色素水平低于正常动物，但它们的ERG仍在正常范围内。
