Functional and morphological abnormalities induced by ouabain intoxication of the rabbit retina

Several researchers have recently used an intravitreal ouabain injection to induce a suitable model of experimental retinopathy and optic neuropathy in various animals. Ouabain administration into the vitreous body of rabbit causes an irreversible degeneration of the retinal layers and consequently of the optic nerve. The degeneration is proportional to the amount of injected drug. Electroretinographic recordings (ERG) show that these structural abnormalities are related to an inhibition of the electric retinal activity as the dose-dependent reduction of ERG waves amplitude has shown. Moreover, ERG and visual evoked responses (VER) measured at the same time evidence that the intravitreal injection of 1.7 nmol ouabain may block the impulse conduction along the optic nerve. This can be proved by the fact that 90 min after an ouabain injection VER disappears, while ERG is only partially reduced. These results are correlated with both morphological observation and autoradiographic studies on 3H-ouabain distribution in different retinal layers.