Local, nonlinear effects of cGMP and Ca2+ reduce single photon response variability in retinal rods.

ABSTRACT: The single photon response (SPR) in vertebrate photoreceptors is inherently variable due to several stochastic events in the phototransduction cascade, the main one being the shutoff of photoactivated rhodopsin. Deactivation is driven by a random number of steps, each of random duration with final quenching occurring after a random delay. Nevertheless, variability of the SPR is relatively low, making the signal highly reliable. Several biophysical and mathematical mechanisms contributing to variability suppression have been examined by the authors. Here we investigate the contribution of local depletion of cGMP by PDE*, the non linear dependence of the photocurrent on cGMP, Ca2+ feedback by making use of a fully space resolved (FSR) mathematical model, applied to two species (mouse and sal

SUBMITTER: Caruso G 

PROVIDER: S-EPMC6894879 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature