The rhodopsin cycle in the developing vertebrate retina

摘要: An integrated study was made of the developmental aspects rhodopsin cycle in albino rat, including measurements content, electroretinogram, and photoreceptor growth. A simplified determination is described which avoids isolation retina, or rod outer segments. Rhodopsin first detected 7 days after birth; it increased rapidly until 22 days, concentration remained constant, while content per eye oontinued to inorease. The electroretinogram appeared at 12 days; amplitudes a- b-waves 21st day slowly thereafter, paralleling concentration. spectral sensitivity curve showed a maximum, coinciding with that difference spectrum rhodopsin. length rods segments both central peripheral areas determined from birth maturity. Growth all these structures slowed abruptly 14 days. Closest parallelism existed between growth up Between amplitude more than doubled, although segment total volume only slightly. development rhodopsin, photoreceptors followed typical curves. Consideration findings light recent electron-microscopic observations on shows appears concomitantly primitive cilium increases sacs; considerable degree sac orientation has occurred.