Biochemical Events Related to Circadian Photoreceptor Shedding

摘要: The renewal of vertebrate photoreceptor outer segments is accomplished by the assembly new disc membranes at base and shedding old distal tip segment (Young Bok, 1969). This intermittent process occurs shortly after onset light in animals entrained to a schedule 12 hours darkness follows circadian rhythm rats (LaVail, 1976, 1980; Goldman et al, 1980) but light-driven frogs (Basinger al., 1976; Hollyfield 1976). In Xenopus laevis, both mechanisms can be expressed depending on experimental conditions (Besharse 1977a). immediate regulation frog resides eye itself (Hollyfield Basinger, 1978). same true rat, with added complication that re-entrainment retinal pacemaker requires input from central nervous system (Teirstein, O’Brien, 1980). These processes have been reviewed recently Besharse (1982).