O'Day W T, Young R W
J Cell Biol. 1978 Mar;76(3):593-604. doi: 10.1083/jcb.76.3.593.
Goldfish were placed on a daily light cycle of 12 h light and 12 h darkness for 18 days or longer. The visual cells and pigment epithelium of the retina were then examined by microscopy at many intervals throughout the cycle. Goldfish rods and cones follow a rhythmic pattern in eliminating packets of photosensitive membranes from their outer segments. Rods shed membranes early in the light period. The detached membranes are ingested by pigment epithelial cells or by ameboid phagocytes, which degrade them during the remainder of the light period. Cones discard membranes from the ends of their outer segments early in the dark period. During the next several hours, this debris is digested by the pigment epithelium or by ameboid phagocytes. Thus, the disposal phase of the outer-segment renewal process is similar in rods and cones, but is displaced in time by about 12 h. There is evidence that this daily rhythm of membrane disposal in rods and cones is a general property of vertebrate visual cells.
金鱼被置于12小时光照和12小时黑暗的日常光照周期下18天或更长时间。然后在整个周期的多个时间间隔通过显微镜检查视网膜的视觉细胞和色素上皮。金鱼的视杆细胞和视锥细胞在从其外段清除光敏膜包时遵循一种节律模式。视杆细胞在光照期早期脱落膜。脱落的膜被色素上皮细胞或变形吞噬细胞摄取，它们在光照期的剩余时间里将其降解。视锥细胞在黑暗期早期从其外段末端丢弃膜。在接下来的几个小时里，这些碎片被色素上皮或变形吞噬细胞消化。因此，外段更新过程的处理阶段在视杆细胞和视锥细胞中相似，但在时间上错开约12小时。有证据表明，视杆细胞和视锥细胞中这种膜处理的日常节律是脊椎动物视觉细胞的普遍特性。
