Light reduces the voltage-dependent inward current in Limulus ventral photoreceptors.

In Limulus ventral photoreceptors, illumination not only increases a specialized light-activated sodium conductance but also modulates voltage-dependent conductances. Previous work has demonstrated that the delayed rectifier current is reduced by light; we report here that the early voltage-dependent inward current is also reduced by light. Furthermore, by maintained during continuous depolarization and that this maintained inward current can be reduced by light. EGTA injection was found to increase the maintained inward current.