Gating Kinetics of the cGMP-Activated Conductance of Retinal Cones

We briefy summarize here a study of the cyclic GMP-activated conductance in retinal cones. With its lack of desensitization and fast gating kinetics, this conductance is very similar to the homologous conductance in rods. The lack of channel desensitization permits a steady dark current to be maintained, while the fast gating kinetics allow the channel to act as a rapid sensor for the decrease in free cGMP concentration in the photoreceptor outer segment during illumination.