Morphological Components Associated With Frog Cone Outer Segment Disc Margins

摘要: The two margin morphologies of frog retinal cone outer segment (COS) discs were examined by thin sectioning, freeze-fracture, and deep-etch, rotary shadowing techniques. disc adjacent to the connecting cilium, which morphologically resembles terminal loop rod (ROS) discs, exhibited a distinctive staining density tightly apposed membrane surface facing lumen. This was crescent-shaped in longitudinal sections, continuous band cross-sections. Associated with opposite additional extracellular structures observed: globular located at edge forming margin, filaments axially interconnecting margins. densities spaced regular intervals along margin. Where these margins calycal processes, appeared span gap interconnect membranes COS process. Distinctive intramembrane particles observed both freeze-fracture. distribution filamentous elements suggests that they may have role maintaining radial dimensions axial spacing associated an framework. Invest Ophthalmol Vis Sci 28:646-657, 1987