title: The sensitivity of rat rod outer segment disc shedding to light.
abstract: Albino rats were raised in cyclic lighting and subjected to either constant light inhibition of the shedding peak or a 10 hr phase advance in the lighting schedule, with lighting levels of varied intensity. All responses followed sigmoid curves of shedding vs. intensity. For constant light inhibition the curve had a shallow slope with a 50% peak at 0.85 ft-cd. Shedding after a phase shift showed a steep curve with a 50% peak at 0.3 ft-cd when animals were observed at 9:30 P. M. and a shallow slope with a 50% peak at 0.003 ft-cd when observed at 7:30 A. M. It is concluded that the mechanisms of shedding inhibition and phase shifts in the shedding rhythm differ with respect to the role of light.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D005260:Female; D008027:Light; D008297:Male; D010786:Photoreceptor Cells / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012374:Rod Cell Outer Segment / Q000502:physiology* / Q000648:ultrastructure