Dark continuous noise from visual pigment as a major mechanism underlying rod-cone difference in light sensitivity.

ABSTRACT: Retinal rods and cones underlie scotopic and photopic vision, respectively. Their pigments exhibit spontaneous isomerizations (quantal noise) in darkness due to intrinsic thermal energy. This quantal noise, albeit exceedingly low in rods, dictates the light threshold for scotopic vision. The same quantal noise in cones, however, is too low to explain the much higher diurnal light threshold. Separately, a dark continuous noise is present in rods, long accepted to originate from an intrinsic random activation of the cyclic guanosine monophosphate (cGMP)-phosphodiesterase enzyme mediating phototransduction downstream of the pigment. Here, we report the surprising finding that most of this rod dark continuous noise actually originates from rhodopsin itself. Importantly, we found the same conti

SUBMITTER: Chai Z 

PROVIDER: S-EPMC11665912 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature