PDF(Pubmed)
Abstract：
The specific arrangement and distribution of photoreceptors in the retina can vary among different fish species, with each species exhibiting adaptations related to its habitat, behavior, and visual requirements. Poecilia sphenops, a diurnal fish, was the focus of this study. The retinas of a total of eighteen Molly fish were investigated utilizing light and electron microscopy. The retina exhibited a square mosaic pattern of the inner segments of cones. This pattern comprised double cones positioned along the sides of a square, with two types of single cones situated at the center and corners of the square arrangement across the entire retina. The corner cones were slightly shorter than the central ones. Additionally, the outer plexiform layer contained both cone pedicles and rod spherules. The rod spherule consisted of a single synaptic ribbon arranged in a triad or quadrat junctional arrangement within the invaginating free ends of the horizontal and bipolar cell processes. On the other hand, cone pedicles have more than one synaptic ribbon in their junctional complex. The inner nuclear layer consisted of the amacrine, bipolar, Müller, and horizontal cell bodies. Müller cell processes, expressing GFAP, extended across all retinal layers, segmenting the deeper retina into alternating fascicles of optic axons and ganglion cells. The outer and inner plexiform layers showed many astrocyte cell processes expressing GFAP. In conclusion, the current study is the first record of the retinal structures of Molly fish. This study illustrated the mosaic arrangement of photoreceptors and GFAP expression patterns of astrocytes and Müller cells. The presence of three cone types, coupled with a sufficient number of rods, likely facilitates motion awareness for tasks like finding food and performing elaborate mating ceremonies.
摘要：
视网膜中光感受器的特定排列和分布在不同的鱼类物种之间可能有所不同，每个物种都表现出与其栖息地相关的适应性，行为，和视觉要求。PoeciliaSphenops,一条昼夜的鱼，是本研究的重点。利用光学和电子显微镜研究了总共18条Molly鱼的视网膜。视网膜显示出锥体内段的方形马赛克图案。这种图案包括沿着正方形的两侧定位的双锥体，有两种类型的单锥位于整个视网膜的正方形排列的中心和角落。角锥比中心锥稍短。此外,外丛状层包含圆锥椎弓根和杆状球。杆状球体由单个突触带组成，该突触带在水平和双极细胞过程的内陷自由端内以三元组或四元组交界排列。另一方面,圆锥椎弓根在其连接复合体中有一个以上的突触带。内核层由无长突神经组成，双极,穆勒,和水平细胞体。穆勒细胞过程，表达GFAP,延伸到所有的视网膜层，将较深的视网膜分割成视神经轴突和神经节细胞的交替束。外部和内部丛状层显示许多表达GFAP的星形胶质细胞过程。总之,目前的研究是对Molly鱼的视网膜结构的首次记录。这项研究说明了星形胶质细胞和Müller细胞的光感受器和GFAP表达模式的镶嵌排列。三种锥形的存在，加上足够数量的杆，可能会促进运动意识的任务，如寻找食物和执行复杂的交配仪式。
