黄鳍鲷视网膜结构和超微结构的研究

STUDY ON THE RETINAL STRUCTURE AND ULTRASTRUC-TURE OF SPARUS LATUS HOUTTUYN

于1983—1984年,作者以光镜和电镜对采集于厦门海区的黄鳍鲷(Sparus latusHouttuyn)视网膜结构和超微结构进行观察,结果表明:视网膜中存在大量视锥和视杆细胞,其视锥细胞可分为单锥(SC)和双锥(TC)两种;视网膜颞侧边缘区为视锥、双极、无长突和神经节细胞的高密度区,该区单位面积(0.01mm^2)有双锥169—177个,单锥80—86个;双锥与单锥之比约为2:1。视网膜中央区到背-鼻侧边缘区为视杆细胞高密度区,该区单位面积(0.0lmm^2)有视杆细胞5017—4883个。水平细胞四层,最外一层水平细胞与单锥有一对一对应联系。 视锥细胞中,微管存在于椭圆体边缘区和肌样体;微丝分布于细胞内向突起中。视锥带状突触,在明适应视网膜中数量增加;在暗适应视网膜中数量减少。突触小泡密度在明、暗适应视网膜中未见有明显差异。色素上皮细胞中存在多种形态的溶酶体,黑色素颗粒与微丝相联系。

The retinal structure and ultrastructure of Sparus latus Houttuyn were studied by histo-logical methods during the years of 1983-1984. The main results obtained are as follows.The retina contains numerous rods and cones. There are two morphologically distinguishable types of cones, single cone (SC) and twin cone (TC). A specialized region is observed in the temporal periphery in which densities of cone, bipolar, amacrine and ganglion cells are higher than those in other locations. Quantitative count shows that maximum cone density is about 169-177 TC and 80-86 SCper unit aera (0.01mm2). TC:SC≌2:1. The region with maximum density of rods is that from the center to dorso-nasal periphery where there are about 5017-4883 R per unit area (0.01mm2). Cones are arranged in a square mosaic with four twin cones alone the sides and a single cone in the center throughout the retina.Cone microtubules are observed in the myoid and marginal zones of the ellipsoid. Micro-filaments distribute in the axon region. Quantity of synaptic ribbons inside cone pedicles increase in light-but decrease in dark-adapted retina. No remarkable difference in density of cone synaptic vesicles is observed in either light-or dark-adapted retina. In pigment epithelial cells, there are three morphological types of lysosome and granular melanins are observed as being connected with bundle of microfilaments. A globule localizes in the inner segment of SC.The relationship between the retinal structure and habits of the fish is also discussed.