Membrane potential affects photocurrent kinetics in salamander rods and cones.

In both rod and cone photoreceptors, polarization of the cell to positive potentials produces a slowing of the photocurrent. This could occur because, at positive potentials, the rate of removal of internal transmitter is slowed, or because the time for which the channels stay closed after interaction with internal transmitter is prolonged. Ion concentration changes within the cell may also contribute to the time course of the photocurrent.