Kuniyoshi Nobue, Yoshida Yuji, Itoh Yoshiki, Yokota Shin-Ichi, Kuraishi Takeshi, Hattori Shosaku, Kondo Tomohiro, Yoshizawa Midori, Kai Chieko, Kiso Yasuo, Kusakabe Ken Takeshi
Laboratory of Basic Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8515, Japan.
Laboratory of Veterinary Anatomy, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi 753-8515, Japan.
J Vet Med Sci. 2018 Mar 24;80(3):413-420. doi: 10.1292/jvms.17-0418. Epub 2018 Jan 26.
Owl monkeys are the only one species possessing the nocturnal lifestyles among the simian monkeys. Their eyes and retinas have been interested associating with the nocturnal adaptation. We examined the cellular specificity and electroretinogram (ERG) reactivity in the retina of the owl monkeys by comparison with the squirrel monkeys, taxonomically close-species and expressing diurnal behavior. Owl monkeys did not have clear structure of the foveal pit by the funduscope, whereas the retinal wholemount specimens indicated a small-condensed spot of the ganglion cells. There were abundant numbers of the rod photoreceptor cells in owl monkeys than those of the squirrel monkeys. However, the owl monkeys' retina did not possess superiority for rod cell-reactivity in the scotopic ERG responses. Scanning electron microscopic observation revealed that the rod cells in owl monkeys' retina had very small-sized inner and outer segments as compared with squirrel monkeys. Owl monkeys showed typical nocturnal traits such as rod-cell dominance. However, the individual photoreceptor cells seemed to be functionally weak for visual capacity, caused from the morphological immaturity at the inner and outer segments.
夜猴是猿猴中唯一具有夜行性生活方式的物种。它们的眼睛和视网膜一直与夜行性适应相关。我们通过与松鼠猴（分类学上相近且表现出昼行性行为的物种）比较，研究了夜猴视网膜中的细胞特异性和视网膜电图（ERG）反应性。通过眼底镜观察，夜猴没有清晰的中央凹结构，而视网膜整装标本显示神经节细胞有一个小而密集的斑点。夜猴的视杆光感受器细胞数量比松鼠猴多。然而，在暗视ERG反应中，夜猴的视网膜在视杆细胞反应性方面并不具有优势。扫描电子显微镜观察显示，与松鼠猴相比，夜猴视网膜中的视杆细胞内段和外段非常小。夜猴表现出典型的夜行性特征，如视杆细胞占主导。然而，由于内段和外段形态不成熟，单个光感受器细胞的视觉功能似乎较弱。
