Loew E R, Govardovskii V I
Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA.
Vis Neurosci. 2001 Sep-Oct;18(5):753-7. doi: 10.1017/s0952523801185081.
Absorbance spectra of cone outer segments and oil droplets were recorded microspectrophotometrically in the retina of the red-eared turtle, Trachemys scripta elegans. There are four cone visual pigments, with lambda(max) = 617 nm (red sensitive), 515 nm (green sensitive), 458 nm (blue sensitive), and 372 nm (UV-sensitive). The red-sensitive pigment resides in single cones with red or orange oil droplets, and in both members of double cones. The principal member of the double cone contains an orange oil droplet, and the accessory member is droplet free. The green-sensitive pigment is situated in single cones with orange/dark yellow droplets. The blue-sensitive pigment is combined with the UV-absorbing oil droplet in single cones. The UV-sensitive pigment resides in single cones with clear oil droplets that exhibited virtually no absorbance down to 325 nm. Thus, seven types of cones can be identified based on their morphology, oil droplet color, and the visual pigment absorbance. At the moment, this is the most complex cone system described for vertebrates.
用显微分光光度法记录了红耳龟（滑龟）视网膜中视锥细胞外段和油滴的吸收光谱。有四种视锥视觉色素，其最大吸收波长分别为617纳米（对红色敏感）、515纳米（对绿色敏感）、458纳米（对蓝色敏感）和372纳米（对紫外线敏感）。对红色敏感的色素存在于带有红色或橙色油滴的单视锥细胞以及双视锥细胞的两个成员中。双视锥细胞的主要成员含有一个橙色油滴，附属成员没有油滴。对绿色敏感的色素位于带有橙色/深黄色油滴的单视锥细胞中。对蓝色敏感的色素与单视锥细胞中吸收紫外线的油滴结合。对紫外线敏感的色素存在于带有透明油滴的单视锥细胞中，这些油滴在325纳米以下几乎没有吸收。因此，根据视锥细胞的形态、油滴颜色和视觉色素吸收情况，可以识别出七种类型的视锥细胞。目前，这是脊椎动物中描述的最复杂的视锥细胞系统。
