FINE-STRUCTURE OF THE LAMPREY PHOTORECEPTORS AND RETINAL-PIGMENT EPITHELIUM (PETROMYZON-MARINUS L)
FINE-STRUCTURE OF THE LAMPREY PHOTORECEPTORS AND RETINAL-PIGMENT EPITHELIUM (PETROMYZON-MARINUS L)
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DOI：
10.1016/0014-4835(79)90165-9
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发表时间：
1979-01-01
影响因子：
3.4
通讯作者：
GRAVES, DA
中科院分区：
文献类型：
--
作者：
DICKSON, DH;GRAVES, DA
用电镜观察了七鳃鳗视网膜感光细胞和色素上皮细胞。无血管视网膜色素上皮细胞表面特化，顶端微绒毛和基底内折。这些细胞含有无数的髓样小体，一些吞噬体和残留体，以及稀疏的位于顶部的黑色素颗粒。在视网膜中描述了两种类型的感光细胞。长感受器具有圆锥形的外节，细长的肌样区，其核位于外核层的外部，靠近外界膜。在这些细胞的外丛状层的深处发现了形的突触终末，其电子密度低于短受体的电子密度，并且它们的突触囊泡似乎比长受体终末中的突触囊泡密度低。短感受器具有细长的外节，其核位于外核层的较深处，而球形突触终末位于外丛状层的巩膜区域。两种细胞类型的外节在超微结构水平上显示出相似的锥形特征，由双膜盘的膜结合堆叠组成，其中一些与细胞外空间连续。两种类型的感受器的外节通过细长的纤毛柄与内节连接，并被萼突包围。放射自显影分析表明，在长和短受体的感光细胞外节的蛋白质更新发生在一个类似的扩散方式，从而引起的建议，这两种感光细胞类型的视网膜中的P. marinus锥。
The retinal photoreceptor cells and pigment epithelium of the lamprey, P. marinus were examined with EM. The pigment epithelial cells in this avascular retina are characterized by surface specializations in the form of apical microvilli and basal infoldings. These cells contain myriad myeloid bodies, some phagosomes and residual bodies, and sparse, apically positioned melanin granules. Two types of photoreceptor cells are described in the retina. The long receptors have conical outer segments, slender elongated myoid regions and their nuclei are positioned in the outer portion of the outer nuclear layer near the external limiting membrane. The pyramid-shaped synaptic terminals of these cells are found deep in the outer plexiform layer, are less electron dense than those of the short receptors and their synaptic vesicles appear to be less densely packed than in the long receptor terminals. The short receptors have slender, elongated outer segments, their nuclei are positioned deeper in the outer nuclear layer, while the spherical synaptic terminals are located in the scleral region of the outer plexiform layer. The outer segments of both cell types, show similar cone-like characteristics at the ultrastructural level, being composed of membrane-bound stacks of double-membrane discs, some of which are in continuity with the extracellular space. The outer segment of both types of receptors is joined to the inner segment through a slender ciliary stalk and is surrounded by calycal processes. Autoradiographic analysis shows that protein renewal in the photoreceptor outer segments of long and short receptors takes place in a similar diffuse manner, giving rise to the suggestion that both photoreceptor types in the retina of P. marinus cones.