Noncovalent occupancy of the retinal-binding pocket of opsin diminishes bleaching adaptation of retinal cones.
Bright light bleaches visual pigment and leads to a persistent desensitization of isolated rod and cone photoreceptors called bleaching adaptation. Bleaching adaptation results from the combined effects of pigment depletion and adaptational modulation of certain cellular reactions in the visual transduction cascade. Here, we present evidence that in solitary cone photoreceptors isolated from the salamander retina, the latter effect is due to the presence of free opsin in the outer segment. Also, we demonstrate that this "opsin adaptation" can be reversed by treating the cells with synthetic retinoids similar to 11-cis retinal but having polyene chains too short to form protonated Schiff base attachments to opsin.
Department of Physiology, Boston University School of Medicine, Massachusetts 02118.
J
J
Jin
R K
RK
Crouch
D W
DW
Corson
B M
BM
Katz
E F
EF
MacNichol
M C
MC
Cornwall
D000222:Adaptation, Physiological; D000557:Ambystoma; D000818:Animals; D004594:Electrophysiology; D008027:Light; D011930:Reaction Time; D012160:Retina / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology* / Q000528:radiation effects; D012168:Retinal Pigments / Q000528:radiation effects*; D012176:Retinoids / Q000737:chemistry / Q000494:pharmacology; D012374:Rod Cell Outer Segment / Q000378:metabolism; D017299:Rod Opsins / Q000378:metabolism*
D012168:Retinal Pigments; D012176:Retinoids; D017299:Rod Opsins; C083482:7-(2,2,6-trimethylcyclohexen-1-yl)-5-methyl-2,4,6-heptatrienal