Nimodipine, a voltage-sensitive calcium channel antagonist, fails to ameliorate light-induced retinal degeneration in rat.

A recent study demonstrated the amelioration of light-induced photoreceptor degeneration by flunarizine and suggested that the protective effect achieved by the drug may be due to the inhibition of inositol 1,4,5-trisphosphate-induced calcium release from intracellular stores or the inhibition of calcium entry through putative voltage-sensitive calcium channels. In the current study, we investigated the effect of nimodipine, a specific voltage-sensitive calcium channel blocker, in light-induced retinal degeneration to further define the factors involved in the retinal degenerative process. Morphological, morphometric, and biochemical results demonstrated that nimodipine was ineffective in ameliorating light-induced retinal degeneration, and implied that calcium entry through voltage-sensitive channels is unlikely to be involved in this disease process, and inositol 1,4,5-trisphosphate-induced calcium release from intracellular stores may play a dominant role in light-induced photoreceptor cell damage.