In the present study, we histologically examined the effects of nilvadipine on neuronal injury induced by intravitreal (i.v.) N -methyl- D -aspartate (NMDA) (200 nmol/eye) and intravitreal NOC12 (400 nmol/eye), a nitric oxide donor, in the rat retina. Morphometric evaluation at 7 d after injection of NMDA or NOC12 showed that treatment with nilvadipine (1 mg/kg, i.v.) 15 min prior to injection of NMDA or NOC12 dramatically reduced the retinal damage. These results suggest that nilvadipine protects neurons against excitotoxic injury in the rat retina in vivo at least in part via an antioxidative effect.